Inserting markup on the legacy editor does not work

Issue Summary

Upon trying to insert markup in the legacy editor, the Insert button no longer allows it to be added, making the macro/preview configuration only display blank content.

Steps to Reproduce

1. Edit a page using the legacy editor.
2. Tap the insert/"+" button on the editor toolbar and select Markup
3. Add your markup to the macro's preview and tap Insert

Expected Results

The Markup should be added to the page.

Actual Results

The macro preview becomes blank and the following is noticed in the browser's console:

Uncaught TypeError: e.api is not a function
    at fn (editor_plugin_src.js:192:10)
    at HTMLButtonElement.action (editor_plugin_src.js:396:15)
    at HTMLButtonElement._onclick (batch.js?externals=__local-default__&locale=en-US:792:314)
    at HTMLButtonElement.dispatch (1.7.2.1-confluence-custom-m07.js:1:32234)
    at HTMLButtonElement.s (1.7.2.1-confluence-custom-m07.js:1:27925) 

There are some additional bugs also tied to the Markup function in the legacy editor:

• https://jira.atlassian.com/browse/CONFCLOUD-65789 - Inserting Markdown on Markup Macro does not Work
• https://jira.atlassian.com/browse/CONFCLOUD-73497 - Insert Markup macro is broken on Legacy Editor

Workaround

Use keyboard shortcuts to have the macro added to the editor's body without needing to go through the "Insert" modal:

{markup}