Show sell with woo tour

[Imran92]

Resolves part of https://github.com/Automattic/sensei-pro/issues/2549

Proposed Changes

We were using Sensei's assets loader to load js paths. This will work for Sensei, but when Sensei-pro or any other third party tries to do the same, this won't work. So to make it more widely useable, we're now using callbacks for loading the tours. This will allow more extensibility.

Testing Instructions

1. Please check https://github.com/Automattic/sensei-pro/pull/2555

Pre-Merge Checklist

• PR title and description contain sufficient detail and accurately describe the changes
• Acceptance criteria is met
• Decisions are publicly documented
• Adheres to coding standards (PHP, JavaScript, CSS, HTML)
• All strings are translatable (without concatenation, handles plurals)
• Follows our naming conventions (P6rkRX-4oA-p2)
• Hooks (p6rkRX-1uS-p2) and functions are documented
• New UIs are responsive and use a mobile-first approach
• New UIs match the designs
• Different user privileges (admin, teacher, subscriber) are tested as appropriate
• Legacy courses (course without blocks) are tested
• Code is tested on the minimum supported PHP and WordPress versions
• User interface changes have been tested on the latest versions of Chrome, Firefox and Safari
• "Needs Documentation" label is added if this change requires updates to documentation
• Known issues are created as new GitHub issues

[github-actions]

Test the previous changes of this PR with WordPress Playground.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.77%. Comparing base (3288498) to head (9fead14).
Report is 3 commits behind head on trunk.

Additional details and impacted files

@@            Coverage Diff            @@
##              trunk    #7549   +/-   ##
=========================================
  Coverage     51.77%   51.77%           
- Complexity    11307    11309    +2     
=========================================
  Files           640      640           
  Lines         48116    48121    +5     
  Branches        467      467           
=========================================
+ Hits          24912    24917    +5     
  Misses        22826    22826           
  Partials        378      378           

Files	Coverage Δ
includes/admin/class-sensei-tour.php	90.90% <100.00%> (+0.90%)	⬆️

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[github-actions]

Test the previous changes of this PR with WordPress Playground.

[renatho]

Looks good and the existing tours continue working properly.

[github-actions]

Test the previous changes of this PR with WordPress Playground.