[BUGFIX] Remove mergeIfNotBlank for sys_file_reference

Since the rendering in the Frontend does not merge the values
this setting is removed from the sys_file_reference TCA to
prevent confusion.

Releases: 6.3, 6.2
Resolves: #59972
Change-Id: I242b687a7ce851270022b86561f13eacea4d3949
[BUGFIX] Reset language mode for child object query

This patch makes all child object queries in Extbase ignore the
current language mode which prevents invalid child object references.

Releases: 6.3, 6.2
Resolves: #59971
Change-Id: I0f9e0de9b118fbd3bc49d7b5960285a2a8dce8c8