pidgin/pidgin

Drop PidginCredentialProviderStore.

2021-05-13, Elliott Sales de Andrade
17208bd7a906
Drop PidginCredentialProviderStore.

It's no longer needed now that the prefs use a `GtkListBox`.

Testing Done:
Compile only.

Reviewed at https://reviews.imfreedom.org/r/650/
.bad-ip {
color: @error_fg_color;
text-shadow: 0 1px @error_text_shadow;
background-image: none;
background-color: @error_bg_color;
}
.good-ip {
color: @question_fg_color;
text-shadow: 0 1px @question_text_shadow;
background-image: none;
background-color: @success_color;
}