chore: convert MultimediaActivity to ViewBinding

[david-allison]

• Part of Add View Binding #11116

Approach

• Cherry picked david-allison@fbcd8b2
• Updated to vbpd

How Has This Been Tested?

Brief test using

• Pixel 6 Pro API 33 Emulator - screen opens

Checklist

• 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

[criticalAY]

Thankyou!

[lukstbit]

There are two findViewById calls remaining in the class. The SnackBar related one we probably can't get around but the toolbar can be accessed through the binding.