mautrix-telegram: fix build

With updating `pluggy` to `0.13.0`[1] the way how python modules are
imported during pytest changed which broke all modules that had a
`coding: future_fstrings` annotation at the top which used to be needed
for python <=3.5. This only affected the tests, deploying a
`mautrix-telegram` from master with `doCheck = false;` works fine.

I applied a patch for `mautrix-telegram` which drops python 3.5 compat
(this package is intended to be used as application with python 3.7, so this
should be fine on master/unstable) and modified `mautrix-appservice`
accordingly as a lot of things on master changed since their last
release, so applying a patch didn't work there.

Resolves #71996

[1] faf8cfba4e

pkgs/servers/mautrix-telegram/default.nix

@@ -1,4 +1,4 @@
-{ lib, python3, mautrix-telegram }:
+{ lib, python3, mautrix-telegram, fetchpatch }:
 
 with python3.pkgs;
 
@@ -11,6 +11,15 @@ buildPythonPackage rec {
     sha256 = "1lsi6x5yr8f9yjxsh1rmcd6wnxr6s6rpr720lg7sq629m42d9p1d";
   };
 
+  patches = [
+    (fetchpatch {
+      url = https://github.com/tulir/mautrix-telegram/commit/be6d395ed66d86ec7f13a262f9ae37731987019c.patch;
+      sha256 = "1q69ip17r45yhyrxr0pj8bvqj2grw2l39wak8pi5pm7qrxra93j2";
+    })
+  ];
+
+  disabled = pythonOlder "3.6";
+
   postPatch = ''
     sed -i -e '/alembic>/d' setup.py
   '';