Process blobs array

In the multi-file scenario for snippets we switch to 'blobs' array
instead of direct 'blob' object

app/assets/javascripts/snippets/fragments/snippetBase.fragment.graphql

@@ -11,7 +11,7 @@ fragment SnippetBase on Snippet {
   webUrl
   httpUrlToRepo
   sshUrlToRepo
-  blob {
+  blobs {
     binary
     name
     path

app/assets/javascripts/snippets/mixins/snippets.js

@@ -11,6 +11,7 @@ export const getSnippetMixin = {
       },
       update: data => data.snippets.edges[0]?.node,
       result(res) {
+        this.blobs = res.data.snippets.edges[0].node.blobs;
         if (this.onSnippetFetch) {
           this.onSnippetFetch(res);
         }
@@ -27,6 +28,7 @@ export const getSnippetMixin = {
     return {
       snippet: {},
       newSnippet: false,
+      blobs: [],
     };
   },
   computed: {