Remove an unused layout file

This layout file was copied from Settings app but in LatinIME it has
never been used.  Also, android:onClick attributes in that layout file
are pointing to non-existing method in LatinIME, which causes lint
warnings.

Since tihs files has never been used in LatinIME, there should be no
user-visible behavior change.

Bug: 110757803
Test: tapas LatinIME && make -j
Change-Id: Ib51744979df333ac432aefc54ef7d0f413cf6161