[Fixes #15953] Implement `assert.expect` in each unit test

Refs #15893

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Closes #15484

This reverts commit 1b323762.
This reverts PR #14189 because it caused major regressions.

Fixes #15168.

We'll try to revisit #14167's feature request in Bootstrap v4.

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Fixes #14851

This would only work with transitions but since we disable them for unit tests, this delivers unreliably results.

Fixes #14375.
Closes #14519 by merging it.

Fixes #14167.
Closes #14189 by merging it.

Fixes #14756.
Closes #14767.

Fixes #14561. Big thanks to @wickstargazer.

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Fixes #14553.

Fixes #14322.
Closes #14581.

Leaking tooltips across tests leads to confusion and sadness.

Fixes #13696.
Fixes #13696.
Fixes #14197.
Closes #13718.

- is(':visible') seems to be the only reliable check, without a refactoring of how hoverState is used
- tests need improvement

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Refs #14090.
Also, fix one typo.

Generates a unique id for tooltip and adds [aria-describedby] to the element
it is called on. Resolves issue #13480

- set up test
- linted the code styles
- passed the tests
- integrated feedback from @cvrebert

primarily adds a data- attribute to the tooltip (and thus, the popover)
to create a self-reference.

#11464 - Fix JS noConflict mode - Refactor all plugins to use an internal reference to the jQuery plugin, because in noConflict mode you can never expect to be defined on the jQuery object