Fix memory leaks & data races in tests (#4772)

* Add a few pre-made sanitizer suppressions

* Test Sanitization: Fix threading issues

* Test Sanitization: Allow deletion of PubSub

We still don't delete it in main code, but this allows us to try
deleting it in tests.

* Test Sanitization: Fix some memory leaks

* fix gtest clang-tidy warning

* const emojis test :-)

tests/src/Emojis.cpp

@@ -17,7 +17,7 @@ TEST(Emojis, ShortcodeParsing)
         QString expectedOutput;
     };
 
-    std::vector<TestCase> tests{
+    const std::vector<TestCase> tests{
         {
             // input
             "foo :penguin: bar",