[⚡tests]: test coverage goal v4.10.0 - 5.0.0

[ala-n]

As for v4.10.0 the goal is to increase overall test coverage by up to 50%

Potential scope (splittable, feel free to create separate issues or skip items):

⚠️ IMPORTANT: split scope by separate branches/PRs, if the target scope is different of the diff, is big enough
⭐ NOTE: split tests by files even if they are related to the same submodule if that is reasonable from support perspective

Major:

• [⚡for esl-utils] fix esl-utils/async/test/promise.raf.ts test file name
• [⚡for esl-mixin-element] cover $$cls, $$attr, $$fire methods with unit tests
• [⚡for esl-trigger] cover esl-trigger target to toggleable request delegation with unit tests
  Note: please make sure you create unit tests encapsulated enough - use fake ESLToggleable implementation, use fake events, and make cases clean, simple, and separated
• [⚡for esl-trigger] cover esl-trigger toggleable tracking functionality with unit tests
  Note: please make sure you create unit tests encapsulated enough - use fake ESLToggleable implementation, use fake events, and make cases clean, simple, and separated
• [⚡for esl-toggleable] cover esl-toggleable basic cases with unit tests
• [⚡for esl-toggleable] cover esl-toggleable-dispatcher with unit tests

Normal:

• [⚡for esl-toggleable] unit tests for body-class | container-class functionality of esl-toggleable
• [⚡for esl-toggleable] unit tests for request:show|hide events of esl-toggleable
• [⚡for esl-trigger] cover esl-trigger hover behavior with unit tests
  Note: please make sure you create unit tests encapsulated enough - use fake ESLToggleable implementation, use fake events, and make cases clean, simple, and separated
• [⚡for esl-toggleable] unit tests for touch hover behavior of esl-toggleable
• [⚡for esl-utils] improve poor esl-utils/dom/attr tests coverage
• [⚡for esl-toggleable] basic integration tests for esl-trigger + esl-toggleable

Minor:

• [⚡for esl-toggleable] unit tests for default a11ty of esl-toggleable
• [⚡for esl-trigger] cover esl-trigger default a11ty with unit tests
  Note: please make sure you create unit tests encapsulated enough - use fake ESLToggleable implementation, use fake events, and make cases clean, simple, and separated
• [⚡for esl-toggleable] unit tests for outside-action functionality of esl-toggleable