Variables: Fixes issue with All variable not being resolved (#27151)

* Variables: Fixes issue with All variable not being resolved

* Tests: update tests according to changes

public/app/features/variables/utils.ts

@@ -1,5 +1,6 @@
 import isString from 'lodash/isString';
 import { ScopedVars } from '@grafana/data';
+import { ALL_VARIABLE_TEXT } from './state/types';
 
 /*
  * This regex matches 3 types of variable reference with an optional format specifier
@@ -58,3 +59,47 @@ export function containsVariable(...args: any[]) {
 
   return !!isMatchingVariable;
 }
+
+export const isAllVariable = (variable: any): boolean => {
+  if (!variable) {
+    return false;
+  }
+
+  if (!variable.current) {
+    return false;
+  }
+
+  if (!variable.current.text) {
+    return false;
+  }
+
+  if (Array.isArray(variable.current.text)) {
+    return variable.current.text.length ? variable.current.text[0] === ALL_VARIABLE_TEXT : false;
+  }
+
+  return variable.current.text === ALL_VARIABLE_TEXT;
+};
+
+export const getCurrentText = (variable: any): string => {
+  if (!variable) {
+    return '';
+  }
+
+  if (!variable.current) {
+    return '';
+  }
+
+  if (!variable.current.text) {
+    return '';
+  }
+
+  if (Array.isArray(variable.current.text)) {
+    return variable.current.text.toString();
+  }
+
+  if (typeof variable.current.text !== 'string') {
+    return '';
+  }
+
+  return variable.current.text;
+};