Use flex to align SVG and text (#25163) (#25260)

Backport #25163 by @wxiaoguang

The code can be as simple as:

```html
<div class="flex-text-block">{{svg "octicon-alert"}} {{svg "octicon-x"}} text (block)</div>
<div><div class="flex-text-inline">{{svg "octicon-alert"}} {{svg "octicon-x"}} text</div> (inline)</div>
<div><button class="ui red button">{{svg "octicon-alert" 24}} {{svg "octicon-x" 24}} text</button></div>
```


![image](1d3c10f1-0bc7-4c26-b236-bad537d5c465)

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/js/components/DashboardRepoList.vue

@@ -19,7 +19,7 @@
           <input @input="changeReposFilter(reposFilter)" v-model="searchQuery" ref="search" @keydown="reposFilterKeyControl" :placeholder="textSearchRepos">
           <i class="icon gt-df gt-ac gt-jc"><svg-icon name="octicon-search" :size="16"/></i>
           <div class="ui dropdown icon button" :title="textFilter">
-            <i class="icon gt-df gt-ac gt-jc gt-m-0"><svg-icon name="octicon-filter" :size="16"/></i>
+            <svg-icon name="octicon-filter" :size="16"/>
             <div class="menu">
               <a class="item" @click="toggleArchivedFilter()">
                 <div class="ui checkbox" ref="checkboxArchivedFilter" :title="checkboxArchivedFilterTitle">