[camera] Fix bug in example

[panmari]

Description

Make the example actually runable by ensuring that flutter widget bindings are initialized. The current version fails on startup.

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[ened]

@panmari - hi! Could you please bump version & add changelog entry?

[panmari]

I was not aware that this is also applicable for documentation-only changes. Done.

[panmari]

Bump, is this now good for merging?

[ened]

LGTM

@mklim could you have a quick look as well?

[mklim]

LGTM, thank you for the fix.