Fix PaliGemma Pad Token Masking During Training #35855 (#35859)
* change order of unmasking of tokens
* library import
* class setup
* test function
* refactor
* add commit message
* test modified
* explict initiliasation of weights + made model smaller
* removed sepete testing file
* fixup
* fixup core
* test attention mask with token types
* tests fixup
* removed PaliGemmaAttentionMaskTest class
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Co-authored-by: sambhavnoobcoder <indosambahv@gmail.com>