Update CP2 snippeting argument defaults (2/2)

Remove the use of the private field

SearchSnippets.SNIPPET_ARGS_PARAM_KEY since we don't need to set
our own snippeting arguments anymore.

Snippeting behavior should remain unchanged.

Bug: 6948882
Change-Id: Ib3ddcbbb852014fb47df2dc6a592aa6d0aaa64fb
1 file changed