feat(front): Add keydown event for Lengthmeasurement (#466)

Added the feature to cancel Lengthmeasurement like its possible in Areameasurement!

Author: pstowasser01

packages/front/src/measurement/LengthMeasurement/index.ts

@@ -303,9 +303,11 @@ export class LengthMeasurement
     if (!viewerContainer) return;
 
     viewerContainer.removeEventListener("pointermove", this.onMouseMove);
+    window.removeEventListener("keydown", this.onKeydown);
 
     if (active) {
       viewerContainer.addEventListener("pointermove", this.onMouseMove);
+      window.addEventListener("keydown", this.onKeydown);
     }
   }
 
@@ -314,4 +316,11 @@ export class LengthMeasurement
       this._vertexPicker.get(this.world);
     }
   };
+
+  private onKeydown = (e: KeyboardEvent) => {
+    if (!this.enabled) return;
+    if (e.key === "Escape") {
+        this.cancelCreation();
+    }
+  };
 }