patch 9.0.2065: EXPAND flag set for filetype option

patch 9.0.2065: EXPAND flag set for filetype option

Problem:  EXPAND flag set for filetype option
Solution: Remove P_EXPAND flag from the 'filetype' option

Remove P_EXPAND flag from the 'filetype' option

Problem:  P_EXPAND flag is erroneously set for 'filetype' option
Solution: Remove the P_EXPAND flag

This flag is used by string options that accept file path values.  See
:help set_env.

This appears to have been included in d5e8c92 and resulted from an
incorrect implementation of 'filetype' completion.

See #12900 for a small discussion.

related: #12900
closes: #13416

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Doug Kearns <dougkearns@gmail.com>