Remove Mozilla Monitor conditionals

[reemhamz]

Description

Firefox Monitor has been rebranded to Mozilla Monitor for about 7+ months now. We have a new rule for L10N strings -- to remove old obsolete strings 2 months after they've turned obsolete (reference found here).

There are a few pages on Bedrock that have updated Mozilla Monitor strings working behind conditionals instead of them being the default. Since enough time has passed, it should be safe to now remove the conditionals around the website, and remove old Firefox Monitor strings being used as fallbacks.

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Success Criteria

• Remove {% if mozilla_monitor %} conditionals being used for strings
• Make Mozilla Monitor Fluent strings the default
• Remove obsolete Firefox Monitor strings
• Switch off related switch in config repo: https://github.com/mozmeao/www-config/blob/main/waffle_configs/bedrock-prod.env#L82