Bug 1750915 - [devtools] Remove backward compatible code for WebExtension targets supporting the watcher. r=jdescottes

Differential Revision: https://phabricator.services.mozilla.com/D136348

devtools/shared/commands/target/target-command.js

@@ -1006,13 +1006,6 @@ class TargetCommand extends EventEmitter {
     // The others which still don't support watcher don't spawn FRAME targets:
     // browser content toolbox and service workers.
 
-    // @backward-compat { version 96 } WebExtension targets only support the
-    // watcher starting with version 96. This if block can be fully removed when
-    // version 96 hits the release channel (cf. comment above).
-    if (!this.watcherFront) {
-      return null;
-    }
-
     return this.watcherFront.getParentWindowGlobalTarget(
       targetFront.browsingContextID
     );