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 :-)

mocks/include/mocks/EmptyApplication.hpp

@@ -7,6 +7,8 @@ namespace chatterino::mock {
 class EmptyApplication : public IApplication
 {
 public:
+    virtual ~EmptyApplication() = default;
+
     Theme *getThemes() override
     {
         return nullptr;