Remove references to supporting per-user flag for msc2654 (#15522)

changelog.d/15522.misc

+Remove references to supporting per-user flag for [MSC2654](https://github.com/matrix-org/matrix-spec-proposals/pull/2654) (#15522).

docs/admin_api/experimental_features.md

 # Experimental Features API
 
 This API allows a server administrator to enable or disable some experimental features on a per-user
-basis. Currently supported features are [msc3026](https://github.com/matrix-org/matrix-spec-proposals/pull/3026): busy 
-presence state enabled, [msc2654](https://github.com/matrix-org/matrix-spec-proposals/pull/2654): enable unread counts,
-[msc3881](https://github.com/matrix-org/matrix-spec-proposals/pull/3881): enable remotely toggling push notifications 
-for another client, and [msc3967](https://github.com/matrix-org/matrix-spec-proposals/pull/3967): do not require
+basis. The currently supported features are: 
+- [MSC3026](https://github.com/matrix-org/matrix-spec-proposals/pull/3026): busy 
+presence state enabled
+- [MSC3881](https://github.com/matrix-org/matrix-spec-proposals/pull/3881): enable remotely toggling push notifications 
+for another client 
+- [MSC3967](https://github.com/matrix-org/matrix-spec-proposals/pull/3967): do not require
 UIA when first uploading cross-signing keys. 
 
 
@@ -19,7 +21,7 @@ provide a body containing the user id and listing the features to enable/disable
 {
    "features": {
       "msc3026":true,
-      "msc2654":true
+      "msc3881":true
    }
 }
 ```
@@ -46,7 +48,6 @@ user like so:
 {
    "features": {
       "msc3026": true,
-      "msc2654": true,
       "msc3881": false,
       "msc3967": false
    }

synapse/rest/admin/experimental_features.py

@@ -33,7 +33,6 @@ class ExperimentalFeature(str, Enum):
     """
 
     MSC3026 = "msc3026"
-    MSC2654 = "msc2654"
     MSC3881 = "msc3881"
     MSC3967 = "msc3967"
 

tests/rest/admin/test_admin.py

@@ -399,7 +399,7 @@ class ExperimentalFeaturesTestCase(unittest.HomeserverTestCase):
             "PUT",
             url,
             content={
-                "features": {"msc3026": True, "msc2654": True},
+                "features": {"msc3026": True, "msc3881": True},
             },
             access_token=self.admin_user_tok,
         )
@@ -420,7 +420,7 @@ class ExperimentalFeaturesTestCase(unittest.HomeserverTestCase):
         )
         self.assertEqual(
             True,
-            channel.json_body["features"]["msc2654"],
+            channel.json_body["features"]["msc3881"],
         )
 
         # test disabling a feature works
@@ -448,10 +448,6 @@ class ExperimentalFeaturesTestCase(unittest.HomeserverTestCase):
         )
         self.assertEqual(
             True,
-            channel.json_body["features"]["msc2654"],
-        )
-        self.assertEqual(
-            False,
             channel.json_body["features"]["msc3881"],
         )
         self.assertEqual(