Adding UI Test (fdl-deprecation)

[srushtisv]

test to verify email link sent successfully

[google-oss-bot]

	1 Warning
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[ncooke3]

clang-format versions disappear from homebrew every few months. main should always be fixed, but branches off of main like this one may stop working until they are synced with main again

[Xiaoshouzi-gh]

can you also add a custom domain test? The custom domain for CI projects should be "firebaseiosauthsample.testdomaindonotuse.com"

[Xiaoshouzi-gh]

The base branch fdl-dep has rebased from main by a force push.
If the CI did not reflect please try following steps:

1. squash all our commits in fdl-dep-test into 1 commit (note down the hash)
   You can do this by git reset --soft to the last commit that is not yours then do a git commit.
2. clone a new branch base of fdl-dep
3. cherry-pick the commit from step 1 to 2.

[srushtisv]

completed in #140000