[MM-48014] Auto-enable Apps Bar by moving EnableAppBar setting to DisableAppBar (#23010)

* auto-enable Apps Bar by moving EnableAppBar setting to DisableAppBar

* update playwright config

* remove EnableAppBar config setting to avoid confusion

* small fixes

---------

Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: Harrison Healey <harrisonmhealey@gmail.com>

e2e-tests/cypress/tests/support/api/on_prem_default_config.json

@@ -370,7 +370,7 @@
         "LinkMetadataTimeoutMilliseconds": 5000,
         "RestrictSystemAdmin": false,
         "UseNewSAMLLibrary": false,
-        "EnableAppBar": true
+        "DisableAppBar": false
     },
     "AnalyticsSettings": {
         "MaxUsersForStatistics": 2500