Refactor tests to understand sendMessage instead of send{Text,Html}Message

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

test/test-utils.js

@@ -94,8 +94,7 @@ export function createTestClient() {
         },
         setAccountData: sinon.stub(),
         sendTyping: sinon.stub().returns(Promise.resolve({})),
-        sendTextMessage: () => Promise.resolve({}),
-        sendHtmlMessage: () => Promise.resolve({}),
+        sendMessage: () => Promise.resolve({}),
         getSyncState: () => "SYNCING",
         generateClientSecret: () => "t35tcl1Ent5ECr3T",
         isGuest: () => false,