Bug 1943119 - Remove ExperimentAPI._store r=nalexander,nimbus-reviewers,emcminn

ExperimentAPI._store used to create a new, separate ExperimentStore in
the child process until bug 1941948 (which was unnecessary) and now only
exists for vestigial reasons. Use ExperimentAPI._manager.store
everywhere.

Differential Revision: https://phabricator.services.mozilla.com/D240414

browser/components/shell/test/browser_doesAppNeedPin.js

@@ -2,15 +2,10 @@
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 ChromeUtils.defineESModuleGetters(this, {
-  ExperimentAPI: "resource://nimbus/ExperimentAPI.sys.mjs",
   ExperimentFakes: "resource://testing-common/NimbusTestUtils.sys.mjs",
   NimbusFeatures: "resource://nimbus/ExperimentAPI.sys.mjs",
 });
 
-registerCleanupFunction(() => {
-  ExperimentAPI._store._deleteForTests("shellService");
-});
-
 let defaultValue;
 add_task(async function default_need() {
   defaultValue = await ShellService.doesAppNeedPin();
@@ -47,8 +42,6 @@ add_task(async function restore_default() {
     return;
   }
 
-  ExperimentAPI._store._deleteForTests("shellService");
-
   Assert.equal(
     await ShellService.doesAppNeedPin(),
     defaultValue,

browser/components/shell/test/browser_setDefaultBrowser.js

@@ -33,8 +33,6 @@ const sendTriggerStub = sinon.stub(ASRouter, "sendTriggerMessage");
 
 registerCleanupFunction(() => {
   sinon.restore();
-
-  ExperimentAPI._store._deleteForTests("shellService");
 });
 
 let defaultUserChoice;
@@ -91,7 +89,6 @@ add_task(async function restore_default() {
 
   userChoiceStub.resetHistory();
   setDefaultStub.resetHistory();
-  ExperimentAPI._store._deleteForTests("shellService");
 
   await ShellService.setDefaultBrowser();