Make PurpleRequestFieldAccount work like a GtkCustomFilter
This makes the filtering better for introspection.
Also, fixed an incorrect type check.
Testing Done:
Enabled Demo and XMPP accounts, then tried the I'dle Mak'er plugin and confirmed that only XMPP showed in its "Set Account Idle Time" action request.
Bugs closed: PIDGIN-17780
Reviewed at https://reviews.imfreedom.org/r/2442/
# SOME DESCRIPTIVE TITLE.
# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
# This file is distributed under the same license as the PACKAGE package.
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"Project-Id-Version: Pidgin\n"
"Report-Msgid-Bugs-To: \n"
"POT-Creation-Date: 2022-10-26 01:46-0500\n"
"PO-Revision-Date: 2017-09-19 23:45+0000\n"
"Last-Translator: Richard Laager <rlaager@wiktel.com>\n"