Default to `false` for `getUploadEnabled`

glean-core/android/src/main/java/mozilla/telemetry/glean/Glean.kt

@@ -344,7 +344,7 @@ open class GleanInternalAPI internal constructor () {
         if (isInitialized()) {
             return LibGleanFFI.INSTANCE.glean_is_upload_enabled().toBoolean()
         } else {
-            return true
+            return false
         }
     }
 

glean-core/csharp/Glean/Glean.cs

@@ -306,7 +306,7 @@ namespace Mozilla.Glean
             }
             else
             {
-                return true;
+                return false;
             }
         }
 

glean-core/ios/Glean/Glean.swift

@@ -269,7 +269,7 @@ public class Glean {
         if isInitialized() {
             return glean_is_upload_enabled() != 0
         } else {
-            return true
+            return false
         }
     }
 

glean-core/python/glean/glean.py

@@ -331,7 +331,7 @@ class Glean:
         if cls.is_initialized():
             return bool(_ffi.lib.glean_is_upload_enabled())
         else:
-            return True
+            return False
 
     @classmethod
     def set_experiment_active(