[A11y] Change role attribute of Recaptcha iframe

[advay26]

Addresses #9300

Problem:

Th Recaptcha iframes on pages like the Forgot Password page and the Report Abuse page were marked with the role presentation by default, but this role (as well as the none role) disables some accessibility properties, which is why FastPass was flagging it.

Previously,

Fix:

Iframes are only allowed to be marked with the roles document, application or img (also presentation or none, but that causes other a11y problems). I changed the role of this iframe to document, and it clears FastPass checks now (on both the pages flagged in the bug, the Forgot Password page and the Report Abuse page).

After the changes,

[ryuyu]

From the looks of the properties here, tab order should still be ok (the original reason we made changes here), but can we do a quick verification that tab order is still ok? Otherwise, looks great!