[ACS-7600] fix imports in dropdown widget

lib/process-services/src/lib/form/widgets/dropdown/dropdown.widget.ts

@@ -22,7 +22,8 @@ import { FormService, FormFieldOption, WidgetComponent, ErrorWidgetComponent } f
 import { ProcessDefinitionService } from '../../services/process-definition.service';
 import { TaskFormService } from '../../services/task-form.service';
 import { CommonModule } from '@angular/common';
-import { TranslateModule } from '@ngx-translate/core';
+import { Component, inject, OnDestroy, OnInit, ViewEncapsulation } from '@angular/core';
+import { AbstractControl, FormControl, ReactiveFormsModule, ValidationErrors, ValidatorFn } from '@angular/forms';
 import { MatFormFieldModule } from '@angular/material/form-field';
 import { MatSelectModule } from '@angular/material/select';
 import { FormsModule } from '@angular/forms';