Add ESR release channel to version selection.

Author: Trikolon

src/components/settings-ui.ts

@@ -168,6 +168,9 @@ export class Settings extends LitElement {
             <option value="release" ?selected=${this.filterFirefoxChannel === "release"}
               >Release (${this.firefoxVersions?.release})</option
             >
+            <option value="esr" ?selected=${this.filterFirefoxChannel === "esr"}
+              >ESR (${this.firefoxVersions?.esr})</option
+            >
           </select>
 
           <label for="rs-env">Remote Settings Environment:</label>

src/settings.ts

@@ -65,7 +65,7 @@ function setRsEnv(env: RSEnvironment, usePreview: boolean) {
 function getFirefoxChannelFilter(): FirefoxChannel {
   const params = new URLSearchParams(window.location.search);
   let firefoxChannel = params.get(QUERY_PARAM_FILTER_FIREFOX_CHANNEL);
-  if (!firefoxChannel || !["nightly", "beta", "release"].includes(firefoxChannel)) {
+  if (!firefoxChannel || !["nightly", "beta", "release", "esr"].includes(firefoxChannel)) {
     return "release";
   }
   return firefoxChannel as FirefoxChannel;