Fix X-Matrix signature validation for incoming requests

For HTTP/1 requests, an inbound Request's URI contains only the path and
query parameters, since there's no way to synthesize the authority part.
This is exactly what we need for the X-Matrix "uri" field.

HTTP/2 requests however can contain the :authority pseudo-header, which
is used to populate the Request's URI. Using a URL that includes an
authority breaks the signature check.

Largely inspired by conduit MR !631
(https://gitlab.com/famedly/conduit/-/merge_requests/631).

Co-authored-by: strawberry <strawberry@puppygock.gay>

src/api/ruma_wrapper/axum.rs

@@ -220,6 +220,16 @@ async fn ar_from_request_inner(
                     CanonicalJsonValue::Object(origin_signatures),
                 )]);
 
+                let x_matrix_uri = parts
+                    .uri
+                    .path_and_query()
+                    .ok_or_else(|| {
+                        Error::BadRequest(
+                            ErrorKind::InvalidParam,
+                            "No HTTP path/query",
+                        )
+                    })?
+                    .to_string();
                 let mut request_map = BTreeMap::from_iter([
                     (
                         "method".to_owned(),
@@ -227,7 +237,7 @@ async fn ar_from_request_inner(
                     ),
                     (
                         "uri".to_owned(),
-                        CanonicalJsonValue::String(parts.uri.to_string()),
+                        CanonicalJsonValue::String(x_matrix_uri),
                     ),
                     (
                         "origin".to_owned(),