web app: Fix bugs in Channel Restore Data

Two bugs fixed:
- List of sources only contains 1 item
- CLicking "Restore Data" too quickly after page loads gives an empty
  source list.

mythtv/html/backend/src/app/config/settings/channel-editor/channel-editor.component.html

@@ -29,7 +29,7 @@ <h2>{{ 'settings.chanedit.title' | translate }}</h2>
                     </p-button>
                     <p-button icon="pi pi-history" (onClick)="restoreDataRequest()"
                         pTooltip="Restore Icons, Visible status, and XMLTV Id after a new scan." tooltipPosition="top"
-                        label="Restore Data" styleClass="p-button-success" class="p-2">
+                        label="Restore Data" styleClass="p-button-success" class="p-2" [disabled]="videoSources.length == 0">
                     </p-button>
                     <div *ngIf="setupService.pageType != 'S' " class="p-2">
                         {{ 'settings.chanedit.delete_message' | translate }}

mythtv/html/backend/src/app/config/settings/channel-editor/channel-editor.component.ts

@@ -411,7 +411,7 @@ export class ChannelEditorComponent implements OnInit {
     this.resSearchDone = false;
     this.allChannels.forEach((entry) => {
       if (entry.MplexId) {
-        if (!this.resSources.find((x) => x.Id = entry.SourceId)) {
+        if (!this.resSources.find((x) => x.Id == entry.SourceId)) {
           const sourceEntry = this.videoSources.find((x1) => x1.Id == entry.SourceId);
           if (sourceEntry)
             this.resSources.push(sourceEntry);