[calls] sip: media-manager: Initialize GStreamer if it's not already initialized

[Evangelos Ribeiro Tzaras <devrtz src gnome org>]

commit a78a2f3dafb5ba5f8a96f5b518f25b1b77f6c2f4
Author: Evangelos Ribeiro Tzaras <devrtz fortysixandtwo eu>
Date:   Tue Mar 1 12:51:40 2022 +0100

    sip: media-manager: Initialize GStreamer if it's not already initialized

 plugins/sip/calls-sip-media-manager.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/plugins/sip/calls-sip-media-manager.c b/plugins/sip/calls-sip-media-manager.c
index 76b17d7d..7f0938de 100644
--- a/plugins/sip/calls-sip-media-manager.c
+++ b/plugins/sip/calls-sip-media-manager.c
@@ -156,7 +156,8 @@ calls_sip_media_manager_class_init (CallsSipMediaManagerClass *klass)
 static void
 calls_sip_media_manager_init (CallsSipMediaManager *self)
 {
-  gst_init (NULL, NULL);
+  if (!gst_is_initialized())
+    gst_init (NULL, NULL);
 
   self->settings = calls_settings_new ();
   g_signal_connect_swapped (self->settings,