Allow scrolling all of the password management list mode screen

[CDRussell]

Task/Issue URL: https://app.asana.com/0/488551667048375/1208758825735780/f

Description

This PR tweaks the layout params for the password recycler view so that the whole view content, already encapsulated in a NestedScrollView, is scrollable.

• Before, you had to scroll on the list view directly, and then only the passwords list would scroll while the rest of the views above were fixed.
• Now, the entire view (including the toggle) is scrollable

Steps to test this PR

• Visit password management view when you have 0 passwords; verify it looks fine and unchanged from before
• Add a single password; verify the password appears immediately below the horizontal divider
• Add enough passwords that they appear down below the screen.
• Verify that scrolling scrolls the whole content, and not just the password list itself
• Verify you can scroll on the list, or scroll on the sync panel, or the text etc… and the whole page scrolls the same way

Screenshots

Current behavior

### New behavior

[CDRussell]

• Allow scrolling all of the password management list mode screen #5377 👈 (View in Graphite)
• develop

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