In this case, null means the field should not be filterable, which is useful
in the cases where it represents a non-authenticated value like a password.
Test: atest CtsAutoFillServiceTestCases:LoginActivityTest#filterTextDisabledUsingNullRegex
Test: atest CtsAutoFillServiceTestCases:LoginActivityTest
Bug: 71359055
Fixes: 72711778
Change-Id: Idc8248f6c95fdb50b934840689616e42ddd6378c