fix: set the default block to stackable/text

[Arukuen]

fixes #3273

Is there a better place where can we set the default block aside aside from editor-loader?

[github-actions]

🤖 Pull request artifacts

file	commit
pr3275-stackable-3275-merge.zip	6ad1f88

[github-actions]

Try this Pull Request in the WordPress playground: https://playground.wordpress.net/?mode=seamless#{"landingPage":"/wp-admin/post-new.php?post_type=page","preferredVersions":{"php":"latest","wp":"latest"},"steps":[{"step":"login","username":"admin","password":"password"},{"step":"installPlugin","pluginZipFile":{"resource":"url","url":"https://raw.githubusercontent.com/gambitph/Stackable/artifacts/pr3275-stackable-3275-merge.zip"}}]}

[bfintal]

Our previous behavior was that hitting enter would create a new Stackable text block.. but only when coming from a Stackable Text or Stackable Heading block. Otherwise, it would still just be a native text block.

This isn't an ideal fix because it will change all default blocks to be Stackable text blocks.