Unify the CI jobs that run the full E2E test suites automatically

[fluiddot]

The full E2E test suites are automatically triggered for the following specific branches:

• trunk
• Dependabot branches (e.g. dependabot/submodules/gutenberg-caab0fe)
• Release branches (e.g. release/1.88.0)

We define a single job for each branch but the same steps are executed (reference). For this reason, I'd propose unifying them into a single job for each platform to simplify the CircleCI configuration.

To test

Regular branch

• Observe in this PR that the Test Android on Device - Full and Test iOS on Device - Full are not automatically triggered. This can be checked in the CircleCI workflow.

Dependabot branch

• Observe in [DO NOT MERGE][TEST] Dependabot branch test #5484 that the Test Android on Device - Full and Test iOS on Device - Full are automatically triggered. This can be checked in the CircleCI workflow.

Release branch

• Observe in [DO NOT MERGE][TEST] Release branch test #5483 that the Test Android on Device - Full and Test iOS on Device - Full are automatically triggered. This can be checked in the CircleCI workflow.

PR submission checklist:

• I have considered adding unit tests where possible.
• I have considered if this change warrants user-facing release notes more info and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

Wanna run full suite of Android and iOS UI tests? Click here and 'Approve' CI job!

[geriux]

LGTM! Thanks for updating this, it looks way better now 🚀