fix TS filterText/insertText updating (microsoft#172616)

fixes microsoft#172419

Author: jrieken

extensions/typescript-language-features/src/languageFeatures/completions.ts

@@ -97,7 +97,7 @@ class MyCompletionItem extends vscode.CompletionItem {
 		this.filterText = this.getFilterText(completionContext.line, tsEntry.insertText);
 
 		if (completionContext.isMemberCompletion && completionContext.dotAccessorContext && !(this.insertText instanceof vscode.SnippetString)) {
-			this.filterText = completionContext.dotAccessorContext.text + (this.insertText || typeof this.label === 'string' ? this.label : this.label.label);
+			this.filterText = completionContext.dotAccessorContext.text + (this.insertText || this.textLabel);
 			if (!this.range) {
 				const replacementRange = this.getFuzzyWordRange();
 				if (replacementRange) {