Use full opacity for online state icons

The green now fully shines while I made the full black ring border a
dark grey.

To increase contrast, on suggestion by @grote.

briar-gtk/data/icons/hicolor/scalable/status/contact_connected.svg

@@ -2,11 +2,11 @@
     xmlns="http://www.w3.org/2000/svg"
     viewBox="0 0 24 24"
     id="vector"
-    opacity="0.56">
+    opacity="1">
     <path
         id="path"
         d="M 12 2 C 6.48 2 2 6.48 2 12 C 2 17.52 6.48 22 12 22 C 17.52 22 22 17.52 22 12 C 22 6.48 17.52 2 12 2 Z M 12 20 C 7.58 20 4 16.42 4 12 C 4 7.58 7.58 4 12 4 C 16.42 4 20 7.58 20 12 C 20 16.42 16.42 20 12 20 Z"
-        fill="#000000"/>
+        fill="#333333"/>
     <path
         id="path_1"
         d="M 0 0 L 24 0 L 24 24 L 0 24 Z"
@@ -45,11 +45,11 @@
     <path
         id="path_6"
         d="M 12 2 C 6.48 2 2 6.48 2 12 C 2 17.52 6.48 22 12 22 C 17.52 22 22 17.52 22 12 C 22 6.48 17.52 2 12 2 Z M 12 20 C 7.58 20 4 16.42 4 12 C 4 7.58 7.58 4 12 4 C 16.42 4 20 7.58 20 12 C 20 16.42 16.42 20 12 20 Z"
-        fill="#000000"/>
+        fill="#333333"/>
     <path
         id="path_7"
         d="M 12 2 C 6.48 2 2 6.48 2 12 C 2 17.52 6.48 22 12 22 C 17.52 22 22 17.52 22 12 C 22 6.48 17.52 2 12 2 Z M 12 20 C 7.58 20 4 16.42 4 12 C 4 7.58 7.58 4 12 4 C 16.42 4 20 7.58 20 12 C 20 16.42 16.42 20 12 20 Z"
-        fill="#000000"/>
+        fill="#333333"/>
     <path
         id="path_8"
         d="M 0 0 L 24 0 L 24 24 L 0 24 Z"

briar-gtk/data/icons/hicolor/scalable/status/contact_disconnected.svg

@@ -2,9 +2,9 @@
     xmlns="http://www.w3.org/2000/svg"
     viewBox="0 0 24 24"
     id="vector"
-    opacity="0.56">
+    opacity="1">
     <path
         id="path"
         d="M 12 2 C 6.48 2 2 6.48 2 12 C 2 17.52 6.48 22 12 22 C 17.52 22 22 17.52 22 12 C 22 6.48 17.52 2 12 2 Z M 12 20 C 7.58 20 4 16.42 4 12 C 4 7.58 7.58 4 12 4 C 16.42 4 20 7.58 20 12 C 20 16.42 16.42 20 12 20 Z"
-        fill="#000000"/>
+        fill="#333333"/>
 </svg>