There is no need to check for file presence when trying to rename imports based on file rename

[sheetalkamat]

Fixes #29031
The perf changed from about 5.7s to 426ms

Info 1889 [15:23:1.527] request:
    {"seq":33,"type":"request","command":"getEditsForFileRename","arguments":{"file":"c:/github/vscode/src/vs/base/common/newPaging.ts","oldFilePath":"c:/github/vscode/src/vs/base/common/paging.ts","newFilePath":"c:/github/vscode/src/vs/base/common/newPaging.ts"}}
Perf 1890 [15:23:1.954] 33::getEditsForFileRename: elapsed time (in milliseconds) 426.4376