[camera] A fix for stopImageStream method which solves a stale images bug

[topnax]

Description

This PR fixes an issue where after starting another image stream subscription after the previous one was stopped, one or more images received were from the previous stream (they were stale). Better description and example is presented in the related issue.

Related Issues

flutter/flutter#54837

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Breaking Change

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[acoutts]

This would be great if it were merged.

[Isakdl]

What is stopping this from being merged? Would love this fix as it currently causes a bug in my app.

[mvanbeusekom]

A fix for this bug is implemented and merged with PR #3344, therefore I will be closing this PR