make tests tolerant to authlib 1.5.2 error messages (#18390)

authlib 1.5.2 now single-quotes error messages in the claims, causing
three tests to fail.

Replace the comparison with a regex that accepts both single or double
quotes.

This succeeds the tests with both authlib 1.5.1 and 1.5.2.

See NixOS/nixpkgs#402797 for context.

### Pull Request Checklist

<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->

* [x] Pull request is based on the develop branch
* [x] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
  - Use markdown where necessary, mostly for `code blocks`.
  - End with either a period (.) or an exclamation mark (!).
  - Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [x] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct
(run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))

Author: flokli

changelog.d/18390.misc

@@ -0,0 +1 @@
+Fixed test failures when using authlib 1.5.2.

tests/rest/client/test_login.py

@@ -1262,18 +1262,18 @@ def test_login_iss(self) -> None:
         channel = self.jwt_login({"sub": "kermit", "iss": "invalid"})
         self.assertEqual(channel.code, 403, msg=channel.result)
         self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
-        self.assertEqual(
+        self.assertRegex(
             channel.json_body["error"],
-            'JWT validation failed: invalid_claim: Invalid claim "iss"',
+            r"^JWT validation failed: invalid_claim: Invalid claim [\"']iss[\"']$",
         )
 
         # Not providing an issuer.
         channel = self.jwt_login({"sub": "kermit"})
         self.assertEqual(channel.code, 403, msg=channel.result)
         self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
-        self.assertEqual(
+        self.assertRegex(
             channel.json_body["error"],
-            'JWT validation failed: missing_claim: Missing "iss" claim',
+            r"^JWT validation failed: missing_claim: Missing [\"']iss[\"'] claim$",
         )
 
     def test_login_iss_no_config(self) -> None:
@@ -1294,28 +1294,28 @@ def test_login_aud(self) -> None:
         channel = self.jwt_login({"sub": "kermit", "aud": "invalid"})
         self.assertEqual(channel.code, 403, msg=channel.result)
         self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
-        self.assertEqual(
+        self.assertRegex(
             channel.json_body["error"],
-            'JWT validation failed: invalid_claim: Invalid claim "aud"',
+            r"^JWT validation failed: invalid_claim: Invalid claim [\"']aud[\"']$",
         )
 
         # Not providing an audience.
         channel = self.jwt_login({"sub": "kermit"})
         self.assertEqual(channel.code, 403, msg=channel.result)
         self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
-        self.assertEqual(
+        self.assertRegex(
             channel.json_body["error"],
-            'JWT validation failed: missing_claim: Missing "aud" claim',
+            r"^JWT validation failed: missing_claim: Missing [\"']aud[\"'] claim$",
         )
 
     def test_login_aud_no_config(self) -> None:
         """Test providing an audience without requiring it in the configuration."""
         channel = self.jwt_login({"sub": "kermit", "aud": "invalid"})
         self.assertEqual(channel.code, 403, msg=channel.result)
         self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
-        self.assertEqual(
+        self.assertRegex(
             channel.json_body["error"],
-            'JWT validation failed: invalid_claim: Invalid claim "aud"',
+            r"^JWT validation failed: invalid_claim: Invalid claim [\"']aud[\"']$",
         )
 
     def test_login_default_sub(self) -> None: