Avoid processing the_content when o2_process_the_content is false

[dd32]

This method isn't using the o2_process_the_content filter which can cause a significant speed issue when the content filters are being run in a context that doesn't require the metadata - such as within a shortcode output in the middle of the page.

On URLs such as this:
https://make.wordpress.org/docs/handbook/documentation-team-handbook/tone-and-voice-guide/
Where all of the notice blocks are shortcodes that render the_content within you'd end up with many duplicate o2 <script>'s which then caused shortcode parsing to timeout.

With this change, the page load time of the above page goes from 100+ seconds to <1s when xDebug is enabled, and from 0.6-0.7s to ~0.4 in production.