Fix Recaptcha rendering on dynamic forms

[loleg]

This patch fixes a bug where the Google Captcha was only rendering correctly on the hardcoded login.html form, but failing to render on dynamically generated forms (like register.html and forgot.html) that use the render_form macro.

The root cause was that RecaptchaFields were falling back to the render_input handler within dribdat/templates/macros/_form.html, which injects class_="form-control" and wrapping label tags, breaking the script tags outputted by Flask-WTF for reCAPTCHA.

By adding an explicit check for field.type == 'RecaptchaField' in the render_form loop, the field is now rendered cleanly within a standard <div class="form-group">, solving the rendering issue.

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PR created automatically by Jules for task 8929327357394990505 started by @loleg

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