[ci] Update release to 3.41

[stuartmorgan-g]

Updates the release step to use 3.41.

Part of https://github.com/flutter/flutter/blob/master/docs/ecosystem/release/Updating-Packages-repo-for-a-stable-release.md

Includes a fix for an out-of-band breakage in tool unit tests, where the behavior of pubspec editing appears to be that it now normalizes final whitespace, causing some overly-picky tests to fail. The tool now:

• does a better job generating test pubspecs that don't have a bunch of extra newlines, and
• ignores trailing whitespace in tests checking file contents that were failing.

[gemini-code-assist]

Note

Gemini is unable to generate a review for this pull request due to the file types involved not being currently supported.

[stuartmorgan-g]

I'll do the other repo update steps later today or Monday, but I wanted to get this landed ASAP to avoid any release issues if packages start requiring 3.41.

[stuartmorgan-g]

The tools unit test seems like it must be an OOB change. Trying to figure out how to repro locally.

[stuartmorgan-g]

@mboetger FYI since you are gardener: this PR includes a fix for the OOB tree breakage in the tool unit tests.