[DocsUI M3] Adjust text direction for file saver input

For RTL languages like iw-IL, the text inside the file picker text
field should be right aligned, use "locale" as the text direction to
achieve that.

Check the screenshot in the attached bug.

Bug: 430670917
Test: Use iw-IL local to launch file saver (force RTL layout won't work)
Flag: com.android.documentsui.flags.use_material3
Change-Id: I6b5e85f49d736702b92c8905c311609ec73ed5cb