RCFilters: Trim spaces in saved query names

RCFilters: Trim spaces in saved query names

Make sure to trim the spaces before saving, and also to verify that
names that contain spaces-only are considered empty.

Also make sure that the same behavior is working when saved queries
are edited - but since the save query button may be disabled, make
sure that any blur event on the input gets us out of the edit mode
either after save or without saving (if the string is invalid)

Bug: T169273
Change-Id: I16da9fcde0bf6be2b854243d7facc80d2860e458