testsuite: arduino-cli should never panic during tests

[cmaglie]

Please check if the PR fulfills these requirements

• The PR has no duplicates (please search among the Pull Requests
  before creating one)
• The PR follows
  our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• UPGRADING.md has been updated with a migration guide (for breaking changes)

• What kind of change does this PR introduce?
  The testsuite is now able to detect arduino-cli panics when running integration tests.

• What is the current behavior?
  The following test

    _, _, err = cli.Run("lib", "upgrade", "Servo")
    require.Error(t, err)

  may pass if arduino-cli panics, but this is wrong, arduino-cli should always return gracefully with a polite error message.

• What is the new behavior?
  The above test fails:

    arduino-cli.go:165: 
                Error Trace:    /home/megabug/Workspace/arduino-cli/internal/integrationtest/lib/arduino-cli.go:165
                                                        /home/megabug/Workspace/arduino-cli/internal/integrationtest/lib/lib_test.go:40
                Error:          "panic: runtime error: invalid memory address or nil pointer dereference
                                [signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0xba23e4]
                            
                                goroutine 1 [running]:
                                github.com/arduino/arduino-cli/commands/lib.upgrade(0xc000139440?, {0xc00047fcd8, 0x1, 0xc00047fca0?}, 0xc00047fca8?, 0x40f667?)
                                        /home/megabug/Workspace/arduino-cli/commands/lib/upgrade.go:61 +0x64
                                github.com/arduino/arduino-cli/commands/lib.LibraryUpgrade({0xc0000ec770?, 0x4?}, 0xc005a9acd0, 0x1?, 0x1?)
                                        /home/megabug/Workspace/arduino-cli/commands/lib/upgrade.go:55 +0x11d
                                github.com/arduino/arduino-cli/cli/lib.runUpgradeCommand(0xc000392a00?, {0xc000297990, 0x1, 0x1?})
                                        /home/megabug/Workspace/arduino-cli/cli/lib/upgrade.go:60 +0x2eb
                                github.com/spf13/cobra.(*Command).execute(0xc000392a00, {0xc000297970, 0x1, 0x1})
                                        /home/megabug/.gvm/pkgsets/go1.19/global/pkg/mod/github.com/spf13/[email protected]/command.go:860 +0x663
                                github.com/spf13/cobra.(*Command).ExecuteC(0xc0002bc780)
                                        /home/megabug/.gvm/pkgsets/go1.19/global/pkg/mod/github.com/spf13/[email protected]/command.go:974 +0x3bd
                                github.com/spf13/cobra.(*Command).Execute(...)
                                        /home/megabug/.gvm/pkgsets/go1.19/global/pkg/mod/github.com/spf13/[email protected]/command.go:902
                                main.main()
                                        /home/megabug/Workspace/arduino-cli/main.go:31 +0x77
                                " should not contain "panic: runtime error:"
                Test:           TestLibUpgradeCommand
                Messages:       arduino-cli panicked
--- FAIL: TestLibUpgradeCommand (22.90s)

• Does this PR introduce a breaking change, and is titled accordingly?
  No

[codecov]

Codecov Report

Merging #1873 (d352f05) into master (3cd782d) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1873   +/-   ##
=======================================
  Coverage   36.67%   36.67%           
=======================================
  Files         231      231           
  Lines       19609    19658   +49     
=======================================
+ Hits         7191     7210   +19     
- Misses      11593    11620   +27     
- Partials      825      828    +3     

Flag	Coverage Δ
unit	36.67% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
internal/integrationtest/arduino-cli.go	83.93% <100.00%> (+0.74%)	⬆️
cli/output/rpc_progress.go	68.75% <0.00%> (-5.80%)	⬇️
commands/instances.go	39.08% <0.00%> (-1.69%)	⬇️
cli/core/search.go	0.00% <0.00%> (ø)
cli/core/update_index.go	0.00% <0.00%> (ø)
commands/daemon/daemon.go	0.00% <0.00%> (ø)
arduino/httpclient/httpclient.go	67.27% <0.00%> (ø)
cli/instance/instance.go	57.69% <0.00%> (+0.41%)	⬆️

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