pidgin/pidgin

Remove pidgin_dialogs_info and gtkdialogs.[ch] as it is now empty.

We have a new API for this and the old dialog just wasn't to fit in there.

Testing Done:
Ran with the turtles and ran the app.

Reviewed at https://reviews.imfreedom.org/r/3109/
TESTS = [
'formatting',
'parser',
'source',
]
foreach prog : TESTS
e = executable(
f'test_ircv3_@prog@', f'test_ircv3_@prog@.c',
dependencies : [birb_dep, libpurple_dep, glib, hasl],
objects : ircv3_prpl.extract_all_objects(),
c_args : ['-DPURPLE_IRCV3_COMPILATION'])
test(f'ircv3_@prog@', e)
endforeach