qt: Make warning label look clickable

The warning label shown on the overview page does not look clickable.
This PR makes the warning label look clickable by removing the 'flat' property.
Additionally, the Maximum Width is updated to fix the small hit-box issue.

src/qt/forms/overviewpage.ui

@@ -68,7 +68,7 @@
               </property>
               <property name="maximumSize">
                <size>
-                <width>30</width>
+                <width>45</width>
                 <height>16777215</height>
                </size>
               </property>
@@ -89,9 +89,6 @@
                 <height>24</height>
                </size>
               </property>
-              <property name="flat">
-               <bool>true</bool>
-              </property>
              </widget>
             </item>
             <item>
@@ -406,7 +403,7 @@
               </property>
               <property name="maximumSize">
                <size>
-                <width>30</width>
+                <width>45</width>
                 <height>16777215</height>
                </size>
               </property>
@@ -427,9 +424,6 @@
                 <height>24</height>
                </size>
               </property>
-              <property name="flat">
-               <bool>true</bool>
-              </property>
              </widget>
             </item>
             <item>