chore: ignore jvm flake when building android sdk in ci

[bitsandfoxes]

building the android sdk in ci was starting to be flaky, see: https://github.com/getsentry/sentry-unity/actions/runs/23897947854/job/69687127898

the jvm errors out but gradle recovers and successfully finishes the build. we already have build-output validation in place. let's ignore the exitcode then.

was missing cache hits due to residual v3 pin. bumped everything to v4.3 while at it.

#skip-changelog

[github-actions]

Semver Impact of This PR

🟢 Patch (bug fixes)

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