fix(Core/Spells): Restore sending SMSG_CAST_FAILED for spells in SPEL…

[avarishd]

…L_STATE_PREPARING state (cast bar in progress)

https://github.com/TrinityCore/TrinityCore/commit/844efbfca84580f7b2bd700f40209515f2aaa959

Correction for https://github.com/azerothcore/azerothcore-wotlk/pull/19082 & https://github.com/azerothcore/azerothcore-wotlk/pull/19101

Changes Proposed:

This PR proposes changes to:

• [x] Core (units, players, creatures, game systems).
• [ ] Scripts (bosses, spell scripts, creature scripts).
• [ ] Database (SAI, creatures, etc).

Issues Addressed:

• Closes

SOURCE:

The changes have been validated through:

• [ ] Live research (checked on live servers, e.g Classic WotLK, Retail, etc.)
• [ ] Sniffs (remember to share them with the open source community!)
• [ ] Video evidence, knowledge databases or other public sources (e.g forums, Wowhead, etc.)
• [x] The changes promoted by this pull request come partially or entirely from another project (cherry-pick). Cherry-picks must be committed using the proper --author tag in order to be accepted, thus crediting the original authors, unless otherwise unable to be found

Tests Performed:

This PR has been:

• [x] Tested in-game by the author.
• [ ] Tested in-game by other community members/someone else other than the author/has been live on production servers.
• [ ] This pull request requires further testing and may have edge cases to be tested.

https://github.com/azerothcore/azerothcore-wotlk/assets/46330494/60459dd7-e1db-420b-ac7c-c95abc8c460e

How to Test the Changes:

• [x] This pull request can be tested by following the reproduction steps provided in the linked issue
• [x] This pull request requires further testing. Provide steps to test your changes. If it requires any specific setup e.g multiple players please specify it as well.

start/cancel casts/channels Check if casts/channels are properly being interrupted (by manually canceling or interrupting with a spell) and if the animations/cast bar is being updated accordingly.

Known Issues and TODO List:

• [ ]
• [ ]

How to Test AzerothCore PRs

When a PR is ready to be tested, it will be marked as [WAITING TO BE TESTED].

You can help by testing PRs and writing your feedback here on the PR's page on GitHub. Follow the instructions here:

http://www.azerothcore.org/wiki/How-to-test-a-PR

REMEMBER: when testing a PR that changes something generic (i.e. a part of code that handles more than one specific thing), the tester should not only check that the PR does its job (e.g. fixing spell XXX) but especially check that the PR does not cause any regression (i.e. introducing new bugs).

For example: if a PR fixes spell X by changing a part of code that handles spells X, Y, and Z, we should not only test X, but we should test Y and Z as well.