[完善]统一社会信用代码改为非必填

src/app/pages/register/register.component.html

@@ -20,7 +20,7 @@
             <mat-form-field>
               <input matInput id="usci" name="usci" #usci="ngModel"
               pattern="^[0-9A-HJ-NP-RTUW-Y]{2}\d{6}[0-9A-HJ-NP-RTUW-Y]{10}$"
-              required ngModel placeholder="请输入统一社会信用代码">
+              ngModel placeholder="请输入统一社会信用代码">
             </mat-form-field>
           </div>
           <div *ngIf="usci.invalid && (usci.dirty || usci.touched)" class="alert-danger">