* feat: Add Secure Keyboard Entry APIs in macOS
Add methods:
- app.isSecureInputEnabled()
- app.setSecureInputEnabled(enabled)
These enable to prevent other process listens keyboard input events.
* fix: lint error in app.md for #20678
* fix: crash app.setSecureInputEnabled() in password textfield
* fix: export Secure keyboard Entry API to only macOS
* fix: lint error in browser_mac.mm for #20678
* test: add test for app.setSecureKeyboardEntryEnabled in macOS
* fix: let setAppLogsPath write to disk on UI thread
Otherwise, the DCHECK in thread_restrictions will fire.
* scope the io allowance more tightly
* oops, scope it tightly in the mac version too