Remove the config options Cypress 14 removed

Cypress 14 removed experimentalSkipDomainInjection (its behavior is the default; injectDocumentDomain: true keeps the old one) and experimentalFetchPolyfill (use cy.intercept() for fetch), and replaced experimentalJustInTimeCompile with justInTimeCompile, which is on by default. Removes the first two, and experimentalJustInTimeCompile: true, from cypress.config.*. experimentalJustInTimeCompile: false is left for FindCypress14Changes.