feat: enable context isolation by default (#26890)

* feat: enable context isolation by default

* chore: set default in ctx iso getter

* spec: make all specs work with the new contextIsolation default

* spec: fix affinity specs

* spec: update tests for new ctx iso default

* spec: update tests for new ctx iso default

* spec: update tests for new ctx iso default

* spec: update tests for new ctx iso default

* chore: move stray prod deps to dev deps

* spec: update tests for new ctx iso default

* turn off contextIsolation for visibility tests

* turn off contextIsolation for <webview> tag nodeintegration attribute loads native modules when navigation happens

Co-authored-by: John Kleinschmidt <jkleinsc@electronjs.org>

spec-main/api-web-request-spec.ts

@@ -495,7 +495,8 @@ describe('webRequest module', () => {
       const contents = (webContents as any).create({
         session: ses,
         nodeIntegration: true,
-        webSecurity: false
+        webSecurity: false,
+        contextIsolation: false
       });
 
       // Cleanup.