Fix all warnings from the cppcoreguidelines-pro-type-member-init clang-tidy check (#4426)

src/widgets/dialogs/ColorPickerDialog.hpp

@@ -71,7 +71,7 @@ private:
         struct {
             QLabel *label;
             ColorButton *color;
-        } selected;
+        } selected{};
 
         struct {
             QColorPicker *colorPicker;
@@ -82,7 +82,7 @@ private:
 
             QLabel *htmlLabel;
             QLineEdit *htmlEdit;
-        } picker;
+        } picker{};
     } ui_;
 
     enum SpinBox : size_t { RED = 0, GREEN = 1, BLUE = 2, ALPHA = 3, END };

src/widgets/dialogs/QualityPopup.hpp

@@ -25,7 +25,7 @@ private:
         QVBoxLayout *vbox;
         QComboBox *selector;
         QDialogButtonBox *buttonBox;
-    } ui_;
+    } ui_{};
 
     QString channelURL_;
 };

src/widgets/dialogs/UserInfoPopup.hpp

@@ -39,8 +39,8 @@ private:
     void updateLatestMessages();
 
     void loadAvatar(const QUrl &url);
-    bool isMod_;
-    bool isBroadcaster_;
+    bool isMod_{};
+    bool isBroadcaster_{};
 
     Split *split_;