fix loading flickering

- [CORE-950]

src/app/utils.ts

@@ -54,7 +54,7 @@ export let bccReady = new Promise((resolve, reject) => {
  */
 const percentageThreshold = 100 / 9;
 let lastPercentage = 0;
-let waitForLoadingAnimation;
+let waitForLoadingAnimation = Promise.resolve();
 let percentagesSet = [ ];
 
 /**
@@ -148,14 +148,14 @@ export function showError() {
  * @return     {string}  additional returnObject
  */
 export async function raiseProgress(percentage: number, returnObj?: any) {
+  // wait for last animation to be finished
+  await this.waitForLoadingAnimation;
+
   lastPercentage += percentage;
   if (lastPercentage > 100) {
     lastPercentage = 100;
   }
 
-  // wait for last animation to be finished
-  await this.waitForLoadingAnimation;
-
   // set the percentage only, if it wasn't set before
   if (!percentagesSet[lastPercentage]) {
     percentagesSet[lastPercentage] = true;