Don't crash if decrypt fails.

.gitignore

@@ -1,6 +1,7 @@
 # OS-Specific junk.
 .DS_Store
 Thumbs.db
+*~
 
 # IntelliJ
 .idea

platform-darwin/Source/Mac/MPMacAppDelegate.m

@@ -70,7 +70,7 @@ static OSStatus MPHotKeyHander(EventHandlerCallRef nextHandler, EventRef theEven
     @try {
         // Sentry
         [SentrySDK initWithOptions:@{
-                @"dsn"        : decrypt( sentryDSN ),
+                @"dsn"        : NilToNSNull( decrypt( sentryDSN ) ),
 #ifdef DEBUG
                 @"debug"      : @(YES),
                 @"environment": @"Development",

platform-darwin/Source/iOS/MPiOSAppDelegate.m

@@ -45,7 +45,7 @@
     @try {
         // Sentry
         [SentrySDK initWithOptions:@{
-                @"dsn"        : decrypt( sentryDSN ),
+                @"dsn"        : NilToNSNull( decrypt( sentryDSN ) ),
 #ifdef DEBUG
                 @"debug"      : @(YES),
                 @"environment": @"Development",