Made title text follows RTL setting.

Added the required attribute to the XML file for the menu header,
ensuring the text aligns with the left-to-right setting.

Fixes: 380318199
Flag: com.android.wm.shell.enable_bubble_bar
Test: Manual.
RTL off: https://screenshot.googleplex.com/A9tBXxis2Z4iuwN
RTL on: https://screenshot.googleplex.com/3oZWURczRmA9q2c

Change-Id: I2d60bb6e7ddb5504af0ca82fe362f3505dd8d80b