Signet should use sBTC not tBTC.

frontend/src/app/components/amount/amount.component.html

@@ -8,6 +8,7 @@
   <ng-template #default>
     &lrm;{{ satoshis / 100000000 | number : digitsInfo }}
     <ng-template [ngIf]="network === 'liquid'">L-</ng-template>
-    <ng-template [ngIf]="network === 'testnet' || network === 'signet'">t</ng-template>BTC
+    <ng-template [ngIf]="network === 'testnet'">t</ng-template>BTC
+    <ng-template [ngIf]="network === 'signet'">s</ng-template>BTC
   </ng-template>
 </ng-template>