refactor: vanilla extract on Separator and Loader (#5474)

* feat: vanilla extract separator and loader

* fix: use vanilla extract css var

Author: lisalupi

.changeset/rich-crabs-cough.md

@@ -0,0 +1,5 @@
+---
+"@ultraviolet/ui": major
+---
+
+Refactor components `Loader` and `Separator` to use vanilla-extract instead of Emotion

packages/form/src/components/Submit/__tests__/__snapshots__/index.test.tsx.snap

@@ -177,15 +177,6 @@ exports[`Submit > form is invalid 1`] = `
 exports[`Submit > form is submitting 1`] = `
 <DocumentFragment>
   .emotion-0 {
-  -webkit-animation: spin 0.75s linear infinite;
-  animation: spin 0.75s linear infinite;
-}
-
-.emotion-2 {
-  stroke: #d9dadd;
-}
-
-.emotion-4 {
   -webkit-transition: stroke-dashoffset 0.5s ease 0s;
   transition: stroke-dashoffset 0.5s ease 0s;
 }
@@ -208,21 +199,21 @@ exports[`Submit > form is submitting 1`] = `
           aria-valuemin="0"
           aria-valuenow="20"
           aria-valuetext="20%"
-          class="emotion-0 emotion-1"
+          class="uv_tkulld2"
           role="progressbar"
           style="height: 1rem; width: 1rem;"
           viewBox="0 0 100 100"
         >
           <circle
-            class="emotion-2 emotion-3"
+            class="uv_tkulld1"
             cx="50"
             cy="50"
             fill="none"
             r="42"
             stroke-width="16"
           />
           <circle
-            class="emotion-4"
+            class="emotion-0"
             cx="50"
             cy="50"
             fill="none"