Revert "Check if dateBox is disposed on valueChanged (T805571) (#9304)…

…" (#9318)

js/ui/date_box/ui.date_box.mask.js

@@ -316,7 +316,7 @@ const DateBoxMask = DateBoxBase.inherit({
     },
 
     _selectNextPart(step = 0) {
-        if(!this.option("text") || this._disposed) {
+        if(!this.option("text")) {
             return;
         }
 

testing/tests/DevExpress.ui.widgets.editors/datebox.mask.tests.js

@@ -640,18 +640,6 @@ if(devices.real().deviceType === "desktop") {
             this.keyboard.paste("November 10 2018");
             assert.strictEqual(this.$input.val(), "November 10 2018", "pasting correct value is allowed");
         });
-
-        test("exception should not be thrown when the widget disposed on valueChange", (assert) => {
-            this.instance.option({
-                value: new Date(2019, 11, 31),
-                onValueChanged: function(e) {
-                    e.component.dispose();
-                }
-            });
-
-            this.keyboard.type("1").blur();
-            assert.strictEqual(this.$input.val(), "January 31 2019", "value is correct");
-        });
     });