Goodbye to Blip-2 doctests (#21566)

Byebye Blip-2 doctest
Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>

utils/documentation_tests.txt

@@ -35,7 +35,6 @@ src/transformers/models/blenderbot/configuration_blenderbot.py
 src/transformers/models/blenderbot/modeling_blenderbot.py
 src/transformers/models/blenderbot_small/configuration_blenderbot_small.py
 src/transformers/models/blenderbot_small/modeling_blenderbot_small.py
-src/transformers/models/blip_2/modeling_blip_2.py
 src/transformers/models/blip/modeling_blip.py
 src/transformers/models/bloom/configuration_bloom.py
 src/transformers/models/camembert/configuration_camembert.py