fix: git branch button size inconsistent

Author: devvaannsh

src/extensions/default/Git/styles/git-styles.less

@@ -1091,8 +1091,13 @@
     .git-panel-branch {
         display: inline-block;
         vertical-align: middle;
+        box-sizing: border-box;
+        height: 22px;
+        margin-top: 2px;
         margin-right: 8px;
+        padding: 2px 10px;
         font-size: 12px;
+        line-height: 16px;
         white-space: nowrap;
         cursor: default;
         i {