Rename ut_mimpluginmanager_config to ut_mimpluginmanagerconfig
Rename ut_mimpluginmanager_config to ut_mimpluginmanagerconfig

Because we have ut_mimpluginmanager_config.[h|cpp] files, it would be confusing
otherwise.

RevBy: TrustMe

Full, original commit at 1f5795c210487a662acf1f8f7a1c60d65418057a in maliit-framework

maliit/inputcontext-gtk,maliit/inputcontext-gtk