Add iOS API removeUserAttribute

Author: AliAbdelfattah

src/ios/IBGPlugin.h

@@ -38,4 +38,6 @@
 
 - (void)setUserAttribute:(CDVInvokedUrlCommand *)command;
 
+- (void)removeUserAttribute:(CDVInvokedUrlCommand *)command;
+
 @end

src/ios/IBGPlugin.m

@@ -1246,6 +1246,27 @@ - (void) setUserAttribute:(CDVInvokedUrlCommand*)command
        [self.commandDelegate sendPluginResult:result callbackId:[command callbackId]];
      }
 
+    /**
+     * Removes a given key and its associated value from user attributes.
+     * Does nothing if a key does not exist.
+    */
+     - (void) removeUserAttribute:(CDVInvokedUrlCommand*)command
+     {
+       CDVPluginResult* result;
+
+       NSString* key = [command argumentAtIndex:0];
+
+       if (key) {
+           [Instabug removeUserAttributeForKey:key];
+           result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
+       } else {
+           result = [CDVPluginResult resultWithStatus:CDVCommandStatus_ERROR
+                                      messageAsString:@"key parameter must be provided."];
+       }
+
+       [self.commandDelegate sendPluginResult:result callbackId:[command callbackId]];
+     }
+
    /**
     * Shows one of the surveys that were not shown before, that also have
     * conditions that match the current device/user.