Remove hardcoded chassis in Manage power usage

Simmilar modification to
https://gerrit.openbmc-project.xyz/c/openbmc/webui-vue/+/42988
which removes the hardcoded chassis name from url on Manage power usage
tab. With this modification we are displaying only informations about
first power device. This change also fixes the overwriting existing
power cap value on load.

Signed-off-by: MichalX Szopinski <michalx.szopinski@intel.com>
Change-Id: Ia164db9f2c50d98bc767c0f4729e9572a2d01da1
diff --git a/src/views/ResourceManagement/Power.vue b/src/views/ResourceManagement/Power.vue
index 8e4acdd..cc0cc99 100644
--- a/src/views/ResourceManagement/Power.vue
+++ b/src/views/ResourceManagement/Power.vue
@@ -118,8 +118,15 @@
         return this.powerCapValue !== null;
       },
       set(value) {
-        let newValue = value ? '' : null;
         this.$v.$reset();
+        let newValue = null;
+        if (value) {
+          if (this.powerCapValue) {
+            newValue = this.powerCapValue;
+          } else {
+            newValue = '';
+          }
+        }
         this.$store.dispatch('powerControl/setPowerCapUpdatedValue', newValue);
       },
     },