room-details: Only show members with default PL in view to add custom PLs

It is more consistent with the wording that way.

src/session/view/content/room_details/permissions/add_members_subpage.rs

@@ -3,7 +3,7 @@ use gtk::{
     CompositeTemplate, glib,
     glib::{clone, closure, closure_local},
 };
-use ruma::{OwnedUserId, events::room::power_levels::PowerLevelUserAction};
+use ruma::OwnedUserId;
 use tracing::error;
 
 use super::{MemberPowerLevel, PermissionsSelectMemberRow, PrivilegedMembers};
@@ -120,11 +120,9 @@ mod imp {
                             return false;
                         };
 
-                        // Filter out members whose power level cannot be changed.
-                        permissions.can_do_to_user(
-                            member.user_id(),
-                            PowerLevelUserAction::ChangePowerLevel,
-                        )
+                        // Since this is a view to add custom power levels, filter out members with
+                        // a custom power level already.
+                        member.power_level() == permissions.default_power_level()
                     }
                 ));
             }

src/session/view/content/room_details/permissions/select_member_row.ui

@@ -31,36 +31,21 @@
               <class name="title"/>
             </style>
             <child>
-              <object class="GtkBox">
-                <property name="spacing">6</property>
-                <child>
-                  <object class="GtkLabel" id="display-name">
-                    <property name="halign">start</property>
-                    <property name="ellipsize">end</property>
-                    <binding name="label">
-                      <lookup name="display-name">
-                        <lookup name="member">RoomDetailsPermissionsSelectMemberRow</lookup>
-                      </lookup>
-                    </binding>
-                    <style>
-                      <class name="title"/>
-                    </style>
-                  </object>
-                </child>
-                <child>
-                  <object class="RoleBadge" id="role_badge">
-                    <property name="visible" bind-source="role_badge" bind-property="is-default-role" bind-flags="sync-create | invert-boolean"/>
-                    <binding name="role">
-                      <lookup name="role">
-                        <lookup name="member">RoomDetailsPermissionsSelectMemberRow</lookup>
-                      </lookup>
-                    </binding>
-                  </object>
-                </child>
+              <object class="GtkLabel">
+                <property name="halign">start</property>
+                <property name="ellipsize">end</property>
+                <binding name="label">
+                  <lookup name="display-name">
+                    <lookup name="member">RoomDetailsPermissionsSelectMemberRow</lookup>
+                  </lookup>
+                </binding>
+                <style>
+                  <class name="title"/>
+                </style>
               </object>
             </child>
             <child>
-              <object class="GtkLabel" id="subtitle">
+              <object class="GtkLabel">
                 <property name="hexpand">True</property>
                 <property name="halign">start</property>
                 <property name="ellipsize">end</property>
@@ -77,7 +62,7 @@
           </object>
         </child>
         <child>
-          <object class="GtkCheckButton" id="check_button">
+          <object class="GtkCheckButton">
             <property name="focusable">False</property>
             <property name="active" bind-source="RoomDetailsPermissionsSelectMemberRow" bind-property="selected" bind-flags="sync-create | bidirectional" />
           </object>