fix(plugins): fix rxjs 6 build errors

#2439

src/@ionic-native/plugins/firebase-dynamic-links/index.ts

@@ -1,6 +1,6 @@
 import { Injectable } from '@angular/core';
 import { Plugin, Cordova, IonicNativePlugin } from '@ionic-native/core';
-import { Observable } from 'rxjs/Observable';
+import { Observable } from 'rxjs';
 
 export interface IDynamicLink {
   matchType: 'Weak' | 'Strong';
@@ -52,21 +52,22 @@ export interface IDynamicLink {
   plugin: ' cordova-plugin-firebase-dynamiclinks',
   pluginRef: 'cordova.plugins.firebase.dynamiclinks',
   repo: 'https://github.com/chemerisuk/cordova-plugin-firebase-dynamiclinks',
-  install: 'ionic cordova plugin add cordova-plugin-firebase-dynamiclinks --save --variable APP_DOMAIN="example.com" --variable APP_PATH="/"',
+  install:
+    'ionic cordova plugin add cordova-plugin-firebase-dynamiclinks --save --variable APP_DOMAIN="example.com" --variable APP_PATH="/"',
   installVariables: ['APP_DOMAIN', 'APP_PATH'],
   platforms: ['Android', 'iOS']
 })
 @Injectable()
 export class FirebaseDynamicLinks extends IonicNativePlugin {
-
   /**
    * Registers callback that is triggered on each dynamic link click.
    * @return {Observable<IDynamicLink>} Returns an observable
    */
   @Cordova({
     callbackOrder: 'reverse',
-    observable: true,
+    observable: true
   })
-  onDynamicLink(): Observable<IDynamicLink> { return; }
-
+  onDynamicLink(): Observable<IDynamicLink> {
+    return;
+  }
 }