Update snippet mutation specs

If the blob does not have a rich_viewer attached, the richData property
will be empty.

spec/requests/api/graphql/mutations/snippets/create_spec.rb

@@ -67,7 +67,7 @@ describe 'Creating a Snippet' do
       it 'returns the created Snippet' do
         post_graphql_mutation(mutation, current_user: current_user)
 
-        expect(mutation_response['snippet']['blob']['richData']).to match(content)
+        expect(mutation_response['snippet']['blob']['richData']).to be_nil
         expect(mutation_response['snippet']['blob']['plainData']).to match(content)
         expect(mutation_response['snippet']['title']).to eq(title)
         expect(mutation_response['snippet']['description']).to eq(description)
@@ -93,7 +93,7 @@ describe 'Creating a Snippet' do
       it 'returns the created Snippet' do
         post_graphql_mutation(mutation, current_user: current_user)
 
-        expect(mutation_response['snippet']['blob']['richData']).to match(content)
+        expect(mutation_response['snippet']['blob']['richData']).to be_nil
         expect(mutation_response['snippet']['blob']['plainData']).to match(content)
         expect(mutation_response['snippet']['title']).to eq(title)
         expect(mutation_response['snippet']['description']).to eq(description)

spec/requests/api/graphql/mutations/snippets/update_spec.rb

@@ -56,7 +56,7 @@ describe 'Updating a Snippet' do
       it 'returns the updated Snippet' do
         post_graphql_mutation(mutation, current_user: current_user)
 
-        expect(mutation_response['snippet']['blob']['richData']).to match(updated_content)
+        expect(mutation_response['snippet']['blob']['richData']).to be_nil
         expect(mutation_response['snippet']['blob']['plainData']).to match(updated_content)
         expect(mutation_response['snippet']['title']).to eq(updated_title)
         expect(mutation_response['snippet']['description']).to eq(updated_description)
@@ -78,7 +78,7 @@ describe 'Updating a Snippet' do
         it 'returns the Snippet with its original values' do
           post_graphql_mutation(mutation, current_user: current_user)
 
-          expect(mutation_response['snippet']['blob']['richData']).to match(original_content)
+          expect(mutation_response['snippet']['blob']['richData']).to be_nil
           expect(mutation_response['snippet']['blob']['plainData']).to match(original_content)
           expect(mutation_response['snippet']['title']).to eq(original_title)
           expect(mutation_response['snippet']['description']).to eq(original_description)