Fix handling of mixins for modules with no dependencies defined

[krzksz]

Description (*)

This PR addresses an issue that was outlined in #25587 (comment) and investigated by me afterwards.

This is a regression I have introduced when refactoring mixins module, but it applies only in two cases which are not present in the Magento itself:

// Module defined as anything else then a function with dependencies skipped.
define('my-module', {
  foo: 'bar'
});
// Module defined with dependencies passed as "null".
define('my-module', null, {
  foo: 'bar'
});

which both results in special case where second element of RequireJS's defQueue is null and made the script throw an error when somebody required such module.

Manual testing scenarios (*)

1. Open the store.
2. Open browser console.
3. Paste and execute the following code:

define('my-module', {
  foo: 'bar'
});
require(['my-module', function(){});

4. Verify that no error similar to TypeError: Cannot read property 'map' of null is thrown.

Questions or comments

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds are green)

Resolved issues:

1. resolves [Issue] Fix handling of mixins for modules with no dependencies defined #28340: Fix handling of mixins for modules with no dependencies defined

[m2-assistant]

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[ihor-sviziev]

Failing functional test not related to changes from this PR>

[magento-engcom-team]

Hi @ihor-sviziev, thank you for the review.
ENGCOM-7447 has been created to process this Pull Request

[engcom-Alfa]

✔️ QA Passed

Manual testing scenario:

1. Go to Storefront;
2. Open browser console;
3. Paste and execute the following code:

define('my-module', {
  foo: 'bar'
});
require(['my-module'], function(){});

Before: ✔️

After: ✖️

[sdzhepa]

@magento run Functional Tests B2B,Functional Tests CE

[sdzhepa]

@magento create issue

[engcom-Echo]

@magento run Functional Tests B2B,Functional Tests CE

[engcom-Echo]

Failed functional tests not related to the changes in this PR

[m2-assistant]

Hi @krzksz, thank you for your contribution!
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