Remove form-validation.scss (#2402)

* Move `.form-group label`

* Remove `form-validation.scss`

* Create .changeset/poor-hotels-roll.md

* Lint

Author: simurai

.changeset/poor-hotels-roll.md

@@ -0,0 +1,5 @@
+---
+"@primer/css": major
+---
+
+Remove `form-validation` styles

src/forms/form-group.scss

@@ -70,7 +70,8 @@
   }
 
   label {
-    position: relative;
+    // fix for chrome bug, see https://github.com/github/github/issues/53931
+    position: static;
   }
 
   &.flattened dt, // TODO: Deprecate

src/forms/form-validation.scss

@@ -2,7 +2,6 @@
 @import './form-control.scss';
 @import './form-select.scss';
 @import './form-group.scss';
-@import './form-validation.scss';
 @import './input-group.scss';
 @import './radio-group.scss';
 // new pvc components