Make existing and new issue URLs configurable (#10710)

* Make existing and new issue URLs configurable

* Apply a deep merge over sdk config to allow sane nested structures

* Defaultize

* Fix types

* Iterate

* Add FeedbackDialog snapshot test

* Add SdkConfig snapshot tests

* Iterate

* Fix tests

* Iterate types

* Fix test

test/LegacyCallHandler-test.ts

@@ -305,7 +305,7 @@ describe("LegacyCallHandler", () => {
         MatrixClientPeg.unset();
 
         document.body.removeChild(audioElement);
-        SdkConfig.unset();
+        SdkConfig.reset();
     });
 
     it("should look up the correct user and start a call in the room when a phone number is dialled", async () => {
@@ -516,7 +516,7 @@ describe("LegacyCallHandler without third party protocols", () => {
         MatrixClientPeg.unset();
 
         document.body.removeChild(audioElement);
-        SdkConfig.unset();
+        SdkConfig.reset();
     });
 
     it("should still start a native call", async () => {