[Android] Fixed action buttons layout for custom tabs (uplift to 1.23.x)

[brave-builds]

Uplift of #8480
Resolves brave/brave-browser#9113

Pre-approval checklist:

• You have tested your change on Nightly.
• This contains text which needs to be translated.
  • There are more than 7 days before the release.
  • I've notified folks in #l10n on Slack that translations are needed.
• The PR milestones match the branch they are landing to.

Pre-merge checklist:

• You have checked CI and the builds, lint, and tests all pass or are not related to your PR.

Post-merge checklist:

• The associated issue milestone is set to the smallest version that the changes is landed on.

[kjozwiak]

Uplift into 1.23.x approved after deliberating with @brave/uplift-approvers. QA we'll verify this on 1.23.x once we get an RC. We would need to wait till tomorrow AM to get a Nightly to QA the above before uplifting. In the spirit of getting a 1.23.x RC ready for tomorrow, we're skipping Nightly verification. Worst case, we revert if needed.