fix: Robotoff banner: bring back the pre-Material 3 visual

[g123k]

Hi everyone!

The upgrade to Material 3 has broken some titles. Here's a fix for the Robotoff banner (+ some light shadow around it)

• @teolemon Shouldn't we remove the claim about badges?

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 29 lines in your changes missing coverage. Please review.

Project coverage is 7.05%. Comparing base (4d9c7fc) to head (daeb127). Report is 413 commits behind head on develop.

Files with missing lines	Patch %	Lines
...pp/lib/pages/product/product_questions_widget.dart	0.00%	29 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #5774 +/- ## ========================================== - Coverage 9.54% 7.05% -2.49% ========================================== Files 325 409 +84 Lines 16411 21969 +5558 ========================================== - Hits 1567 1551 -16 - Misses 14844 20418 +5574 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[teolemon]

Agreed @g123k "Become an actor of food transparency"