Fix alignment of url buttons for Blockbase theme

[Imran92]

Fixes https://github.com/Automattic/sensei/issues/5808

Changes proposed in this Pull Request

• Replaced anchor tags with form and button so that we don't have to fight with styles in different themes.

Testing instructions

• Activate the Blockbase theme and Sensei Pro.
• Ensure there's a paid course that you aren't enrolled in, a course that you've completed, one you have made some progress in but not completed. They all should have at least some excerpts or description or something in the course body
• Ensure there's a course that you are enrolled in (free or paid).
• View the Course List block on the frontend and check all of those courses.
• Make sure the action buttons for all of them are aligned and look similar
• Make sure all of those buttons work as expected
• Check with the other popular themes for Sensei and make sure it hasn't broken in any of those

Screenshot / Video

Blockbase - Astra

[codecov[bot]]

Codecov Report

Merging #5814 (28a30ee) into trunk (f4d9f37) will increase coverage by 0.00%. The diff coverage is 100.00%.

:exclamation: Current head 28a30ee differs from pull request most recent head 2c69d1b. Consider uploading reports for the commit 2c69d1b to get more accurate results

@@            Coverage Diff            @@
##              trunk    #5814   +/-   ##
=========================================
  Coverage     46.74%   46.75%           
  Complexity     9737     9737           
=========================================
  Files           464      464           
  Lines         34370    34372    +2     
  Branches        275      275           
=========================================
+ Hits          16067    16069    +2     
  Misses        18098    18098           
  Partials        205      205           

Impacted Files	Coverage Δ
...ncludes/blocks/class-sensei-block-view-results.php	92.85% <100.00%> (+0.26%)	:arrow_up:
...udes/blocks/class-sensei-continue-course-block.php	93.02% <100.00%> (+0.16%)	:arrow_up:
includes/admin/class-sensei-setup-wizard-pages.php	98.07% <0.00%> (ø)

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[m1r0]

JFYI, there is a Course List bug related to this. I'm not sure if the tests are failing because of that or something else.

[merkushin]

Sorry, is it ready for review?

[Imran92]

Sorry, is it ready for review?

Yes it is! 🦃

[donnapep]

Looks like a JS test is failing. Does it seem related to this PR?

[Imran92]

Looks like a JS test is failing. Does it seem related to this PR?

Seems like all the failing tests are from students/student-action-menu/index.test.js file, shouldn't be related to this PR