[INTERNAL][FIX] mdc.FilterBarBase: release validation promise during

clean-up

BCP: 2270170781

Change-Id: I641bb9d8444cca5f0f58d2905306072ad086908e

Author: d027183

src/sap.ui.mdc/src/sap/ui/mdc/filterbar/FilterBarBase.js

@@ -884,7 +884,6 @@ sap.ui.define([
 
 				var fDelayedFunction = function() {
 					this._validate(bFireSearch);
-					this._oValidationPromise = null;
 				};
 				setTimeout(fDelayedFunction.bind(this), 0);
 			}
@@ -1121,6 +1120,7 @@ sap.ui.define([
 		}.bind(this);
 
 		var fnCleanup = function() {
+			this._oValidationPromise = null;
 			this._fRejectedSearchPromise = null;
 			this._fResolvedSearchPromise = null;
 		}.bind(this);