Fix DocBlocks for class WP_Customize_Selective_Refresh

[keesiemeijer]

• The @access tag for the properties $triggered_errors and $current_partial_id is set to private where it should be protected.
• The @access tag for the method handle_error() is set to private where it should be public
• The DocBlocks for the duplicate customize_dynamic_partial_args and customize_dynamic_partial_class filters should point to the documented version in the same file.

[keesiemeijer]

Fix DocBlocks for class WP_Customize_Selective_Refresh

[SergeyBiryukov]

In 39734:

Docs: Correct @access entries and duplicate hook references in WP_Customize_Selective_Refresh.

Props keesiemeijer.
Fixes #39501.