Fix RTL message alignment and add RTL regression stories

[sari-devv]

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Description

Fixes issue #7819:
This PR restores correct Right-To-Left (RTL) message alignment in the conversation view. A previous commit accidentally hardcoded dir="ltr" on the inner message text container, which overrode the dynamic directionality for Arabic and Hebrew messages.

What:

• Removed hardcoded dir="ltr" from the .module-message__text container in Message.dom.tsx.
• Updated Storybook createProps to allow i18n overrides.
• Added MixedRtlAndLtrMessage and DeletedRtl stories to TimelineMessage.dom.stories.tsx.

Why:
The hard-coded dir="ltr" attribute on the message text wrapper forced a Left-To-Right context regardless of the actual message content. Since the container uses text-align: start, this caused RTL messages (like Arabic or Hebrew) to incorrectly align to the left side of the bubble and broke the rendering of bidirectional punctuation.

This attribute was originally added to stabilize the "Delete for everyone" layout icon positioning. However, since those strings are now correctly wrapped in <span dir="auto">, the hard-coded attribute on the parent is no longer necessary and was causing wide-spread RTL regressions.

Technical Details:
OS: MacOS, but the testing was done on Storybook.

• Removing the hard-coded attribute allows the message text to properly inherit the directionality calculated by the message selectors.
• Manual Testing: Two stories were added:

1. MixedRtlAndLtr: Mixes Arabic and English, in a similar way to the image in issue Right To Left (RTL) language (Hebrew) messages are left-aligned instead of right #7819's description, and verified the change. Before and after screenshots are attached.
2. The DeletedRtl story was added to verify that "Delete for everyone" remains stable in RTL contexts. It dynamically imports Arabic strings from _locales/ar/messages.json and mocks the i18n.getIntl() interface to simulate the production environment's usage of the <I18n> component. This ensures that the layout fix is verified against actual RTL text and character-order rules in automated visual tests.

Before vs After Visual Comparison

Before

After

[nehemiagurl]

so... what are the plans regarding this regression? this bug is now landing in production for many users, greatly reducing usability for anyone of the half a billion RTL language speakers, with switching to the LTR interface not improving the situation...

[nirtz89]

This needs to be pushed ASAP.
Over half a billion users are RTL language speakers.

[ayumi-signal]

Thank you for opening the PR and correctly identifying the issue. We ended up fixing just the "ltr" attribute, and will consider adding extra storybook as you've suggested or automated visual tests to detect RTL regressions in the future.

[sari-devv]

My pleasure!

Do I need to close this PR now?

[ayumi-signal]

For now I'll close it. If we end up using the storybook updates I'll let you know.