[ui] Fix undersized color buttons in the 3D map config dialog

Author: nirvn

src/ui/3d/phongmaterialwidget.ui

@@ -29,6 +29,12 @@
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
+     <property name="minimumSize">
+      <size>
+       <width>120</width>
+       <height>0</height>
+      </size>
+     </property>
     </widget>
    </item>
    <item row="1" column="0">
@@ -46,6 +52,12 @@
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
+     <property name="minimumSize">
+      <size>
+       <width>120</width>
+       <height>0</height>
+      </size>
+     </property>
     </widget>
    </item>
    <item row="2" column="0">
@@ -63,6 +75,12 @@
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
+     <property name="minimumSize">
+      <size>
+       <width>120</width>
+       <height>0</height>
+      </size>
+     </property>
     </widget>
    </item>
    <item row="3" column="0">

src/ui/3d/qgslightswidget.ui

@@ -149,6 +149,12 @@
          <verstretch>0</verstretch>
         </sizepolicy>
        </property>
+       <property name="minimumSize">
+        <size>
+         <width>120</width>
+         <height>0</height>
+        </size>
+       </property>
       </widget>
      </item>
      <item row="4" column="0">