MatInput does not clear error state on form reset

**This is my submiting function**

public submitCategoryForm(): void {
this.buttonText = 'Processing...';
this.isClicked = true;

const categoryData = this.categoryForm.value;
this.categoryModel = new CategoryInputModel(
categoryData['title'],
categoryData['imageUrl']
);

this.categoryServices.addNewCategory(this.categoryModel).subscribe(() => {
this.buttonText = 'Add';
this.isClicked = false;
this.categoryForm.reset({ title: '', imageUrl: '' });
});
}

#### What is the use-case or motivation for changing an existing behavior?
After submiting my form (successfully) and reset values of the form, validations for required value pop up. How i can submit my form clear values and to make sure validations are not shown.

#### Which versions of Angular, Material, OS, TypeScript, browsers are affected?
Angular 6, Material 6.4.7

#### Is there anything else we should know?

Riproduci il comportamento a partire dall’entry point submitCategoryForm, in particolare la chiamata categoryForm.reset({ title: '', imageUrl: '' }), utilizzando, se disponibili, le versioni segnalate Angular 6 e Material 6.4.7. Determina se reset debba lasciare nascosti gli errori dei campi obbligatori, quindi aggiungi o aggiorna il test pertinente del form/input per verificare lo stato atteso dopo il reset.

Scritto dal modello di indicizzazione a partire dal testo della issue.