feat: add @mention support in send box (#3281)

* Initial work to mention a user in SendBocx

Signed-off-by: Martin Musale <martinmusale@microsoft.com>

* Move setting mentions to statefulclient

Signed-off-by: Martin Musale <martinmusale@microsoft.com>

* Use chatState.participants to get mention users in select chat

Signed-off-by: Musale Martin <martinmusale@microsoft.com>

* Update to acs/react v1.10.0-beta-1

Signed-off-by: Musale Martin <martinmusale@microsoft.com>

* Show mention on sending a message

Signed-off-by: Musale Martin <martinmusale@microsoft.com>

* Remove unnecessary additions to state client

Signed-off-by: Musale Martin <martinmusale@microsoft.com>

* Fix layout of messages in a div

Signed-off-by: Martin Musale <martinmusale@microsoft.com>

* Refactor out mention lookup options

Signed-off-by: Martin Musale <martinmusale@microsoft.com>

* Use mgt person to render suggestions

Signed-off-by: Martin Musale <martinmusale@microsoft.com>

* Fix rebasing issues

* Update both instances of send box to have similar config

* Add hover state styling

* fix mentions item hover

* Update acs to 1.14.0-beta.1

* Update active state and related styles

* Add mentions to docs comment

* Remove unused vars

* Set scroll to auto, remove unnecessary props for disabled state and make cursor pointer on hover

* Render the selected name temporarily before replacing it with the mgt mention state

* Arrange the mentions with a small gap

* test git status validation

* Revert "test git status validation"

This reverts commit 8c33cc5.

* test git status validation

* Revert "test git status validation"

This reverts commit d7a2e51.

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Signed-off-by: Martin Musale <martinmusale@microsoft.com>
Signed-off-by: Musale Martin <martinmusale@microsoft.com>
Co-authored-by: Mnickii <miaronkirote@gmail.com>