Add hashes if directive already has hash or nonce

Problem/Motivation

Currently if any directive already includes 'unsafe-inline', the module will not add a hash or nonce since it may block functionality.

// Don't make any modifications if closest enabled fallback uses
// 'unsafe-inline'.
if (in_array(Csp::POLICY_UNSAFE_INLINE, $fallbackValue)) {
  return;
}

If the directive also already includes a hash or nonce, however, the new values should be added.

Proposed resolution

When a directive includes 'unsafe-inline', only skip modifying the directive if it also does not contain a hash or nonce source.