add spacing to pipeline feed spinner (#2326)

Ref:
#2162 (comment)

## Before

![image](https://github.com/woodpecker-ci/woodpecker/assets/3391958/d58b5b1d-92e8-4e06-bcf2-4f726fc606e4)

## After

![image](https://github.com/woodpecker-ci/woodpecker/assets/3391958/2474992c-988c-4775-ac5f-e38ed05530a4)

web/src/components/layout/header/ActivePipelines.vue

@@ -1,6 +1,6 @@
 <template>
   <IconButton :title="$t('pipeline_feed')" class="!p-1.5 relative text-current" @click="toggle">
-    <div v-if="activePipelines.length > 0" class="spinner">
+    <div v-if="activePipelines.length > 0" class="spinner m-1">
       <div class="spinner-ring ring1" />
       <div class="spinner-ring ring2" />
       <div class="spinner-ring ring3" />