fix: RTL issues in new conversation form (#12163)

# Pull Request Template

## Description

This PR fixes RTL alignment issues in the new conversation form, removes
the unused
[`form-checkbox`](https://github.com/chatwoot/chatwoot/pull/12151#discussion_r2266333315)
class name and drops the `app-rtl--wrapper` class, which was previously
used for RTL detection in `rtl.scss` (removed earlier)

Fixes https://linear.app/chatwoot/issue/CW-5410/rtl-issues

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)

## How Has This Been Tested?

### Screenshots

<img width="868" height="474" alt="image"
src="https://github.com/user-attachments/assets/45995652-2895-49d5-a651-179090c949ec"
/>
<img width="868" height="656" alt="image"
src="https://github.com/user-attachments/assets/a1cb4415-3fd4-4c9a-bc46-5e07e437d757"
/>
<img width="868" height="656" alt="image"
src="https://github.com/user-attachments/assets/77c8981f-364e-4bf0-bea8-a4c42a76d065"
/>



## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

app/javascript/dashboard/components-next/avatar/Avatar.vue

@@ -207,7 +207,7 @@ watch(
     <!-- Delete Avatar Button -->
     <div
       v-if="src && allowUpload"
-      class="absolute z-20 flex items-center justify-center invisible w-6 h-6 transition-all duration-300 ease-in-out opacity-0 cursor-pointer outline outline-1 outline-n-container -top-2 -right-2 rounded-xl bg-n-solid-3 group-hover/avatar:visible group-hover/avatar:opacity-100"
+      class="absolute z-20 flex items-center justify-center invisible w-6 h-6 transition-all duration-300 ease-in-out opacity-0 cursor-pointer outline outline-1 outline-n-container -top-2 ltr:-right-2 rtl:-left-2 rounded-xl bg-n-solid-3 group-hover/avatar:visible group-hover/avatar:opacity-100"
       @click="handleDismiss"
     >
       <Icon icon="i-lucide-x" class="text-n-slate-11 size-4" />