fix(study-screen): timer on big screens

[BrayanDSO]

if Show answer buttons was disabled, the timer was visible even if disabled

Discovered by looking over the reviewer screenshot tests

Approach

For some reason, a ConstraintLayout Flow resets its children visibility if a new constraint is applied, such as when the answer buttons are hidden on tablets.

How Has This Been Tested?

Sreenshot semi-automated tests

Details

Checklist

Please, go through these checks before submitting the PR.

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[BrayanDSO]

Gonna yolo this one. It's well tested and merging it spares me some time on other PRs.

I'm on the area, so I take full responsability here.

[mikehardy]

Nothing like a new testing modality to expose a bunch of new issues that weren't even known before - kudos for the screenshot infra