Added escaping on several strings in wp-login.php

[OpuRockey]

Ticket: https://core.trac.wordpress.org/ticket/65076

Summary

This PR addresses multiple instances of improperly escaped output in wp-login.php. It ensures that dynamic strings are escaped at the point of output using appropriate WordPress escaping functions, aligning with core security best practices.

Problem

Several strings in wp-login.php were output without proper escaping or with inconsistent escaping. This can lead to:

• Potential security risks (e.g., XSS vulnerabilities)
• Violation of WordPress coding standards regarding output escaping

WordPress recommends escaping data as late as possible (on output) to avoid issues like double-escaping or unsafe rendering.

Solution

• Audited multiple output points in wp-login.php
• Applied appropriate escaping functions based on context:.
• Ensured consistency across all login-related messages and UI elements

Impact

• Improves security by preventing unescaped output
• Aligns with WordPress Core coding standards

Notes

• No backward compatibility issues expected
• Changes are limited to output escaping and do not alter logic or functionality

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[github-actions]

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