Make browser.browser_versions read-only
Make browser.browser_versions read-only

Until we can restrict in Browsable API, and it is ordered

mdn/browsercompat,mdn/browsercompat,mdn/browsercompat,jwhitlock/web-platform-compat,jwhitlock/web-platform-compat,jwhitlock/web-platform-compat,renoirb/browsercompat,renoirb/browsercompat,renoirb/browsercompat