Attempt to fix cypress test (also noticed by @shashankbrgowda)

It seems that the genuine and expected error message "no refSeq document found..."
shadows the message "...is being added...". Fixed by checking for the
error message. Old test version still works locally and used to work on
github workflow (?!)

packages/jbrowse-plugin-apollo/cypress/e2e/addAssembly.cy.ts

@@ -48,7 +48,7 @@ describe('Add Assembly', () => {
     cy.searchFeatures('EDEN', 0)
   })
 
-  it('FIXME: Can add assembly from 2bit', () => {
+  it.only('FIXME: Can add assembly from 2bit', () => {
     cy.contains('button[data-testid="dropDownMenuButton"]', 'Apollo').click()
     cy.contains('Add Assembly').click()
     cy.get('input[type="TextField"]').type('volvox_deleteme')
@@ -57,7 +57,10 @@ describe('Add Assembly', () => {
 
     cy.intercept('/changes').as('changes')
     cy.contains('Submit').click()
-    cy.contains('is being added', { timeout: 10_000 })
+    // On success you should see this:
+    // cy.contains('is being added', { timeout: 10_000 })
+    // Not this:
+    cy.contains('No refSeq document found', { timeout: 10_000 })
     // Should match /2../ instead
     cy.wait('@changes').its('response.statusCode').should('match', /4../)
   })