Roll customer_testing from b4cc09721 to 6a6d0963c (3 commits) (#162763)

Looks like this is the first roll since this pin was introduced in
#162041 / #162048.

For fun and the possible convenience of the next person doing one of
these, here's the command I used to generate the log below:

$ git log --oneline --no-decorate --format='%cs %aE %s' b4cc09721.. \
        | perl -pe 's,#,flutter/tests#,g'

b4cc09721...6a6d0963c

2025-02-05 greg@zulip.com Re-land "Update Zulip tests and re-enable
(flutter/tests#441)" (flutter/tests#446)
2025-01-30 goderbauer@google.com Update contact for pkg:animations
(flutter/tests#447)
2025-01-24 matanlurey@users.noreply.github.com Add a PR template that
explains updating `tests.version` (flutter/tests#445)

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

dev/customer_testing/tests.version

@@ -1 +1 @@
-b4cc097211814cfb0e1f08affb4574cf7de6b1cd
+6a6d0963c486da4c0b9387e5a5f6674877023064