feat: Standardize rich editor across all channels (#12600)

# Pull Request Template

## Description

This PR includes,

1. **Channel-specific formatting and menu options** for the rich reply
editor.
2. **Removal of the plain reply editor** and full **standardization** on
the rich reply editor across all channels.
3. **Fix for multiple canned responses insertion:**
* **Before:** The plain editor only allowed inserting canned responses
at the beginning of a message, making it impossible to combine multiple
canned responses in a single reply. This caused inconsistent behavior
across the app.
* **Solution:** Replaced the plain reply editor with the rich
(ProseMirror) editor to ensure a unified experience. Agents can now
insert multiple canned responses at any cursor position.
4. **Floating editor menu** for the reply box to improve accessibility
and overall user experience.
5. **New Strikethrough formatting option** added to the editor menu.

---

**Editor repo PR**:
https://github.com/chatwoot/prosemirror-schema/pull/36

Fixes https://github.com/chatwoot/chatwoot/issues/12517,
[CW-5924](https://linear.app/chatwoot/issue/CW-5924/standardize-the-editor),
[CW-5679](https://linear.app/chatwoot/issue/CW-5679/allow-inserting-multiple-canned-responses-in-a-single-message)

## Type of change

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

## How Has This Been Tested?

### Screenshot
**Dark**
<img width="850" height="345" alt="image"
src="https://github.com/user-attachments/assets/47748e6c-380f-44a3-9e3b-c27e0c830bd0"
/>

**Light**
<img width="850" height="345" alt="image"
src="https://github.com/user-attachments/assets/6746cf32-bf63-4280-a5bd-bbd42c3cbe84"
/>


## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] 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
- [x] 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

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: Pranav <pranav@chatwoot.com>
Co-authored-by: Vinay Keerthi <11478411+stonecharioteer@users.noreply.github.com>

app/javascript/dashboard/components-next/Editor/Editor.vue

@@ -19,7 +19,6 @@ const props = defineProps({
   },
   enableVariables: { type: Boolean, default: false },
   enableCannedResponses: { type: Boolean, default: true },
-  enabledMenuOptions: { type: Array, default: () => [] },
   enableCaptainTools: { type: Boolean, default: false },
   signature: { type: String, default: '' },
   allowSignature: { type: Boolean, default: false },
@@ -102,7 +101,6 @@ watch(
         :disabled="disabled"
         :enable-variables="enableVariables"
         :enable-canned-responses="enableCannedResponses"
-        :enabled-menu-options="enabledMenuOptions"
         :enable-captain-tools="enableCaptainTools"
         :signature="signature"
         :allow-signature="allowSignature"
@@ -139,19 +137,6 @@ watch(
 .editor-wrapper {
   ::v-deep {
     .ProseMirror-menubar-wrapper {
-      @apply gap-2 !important;
-
-      .ProseMirror-menubar {
-        @apply bg-transparent dark:bg-transparent w-fit left-1 pt-0 h-5 !top-0 !relative !important;
-
-        .ProseMirror-menuitem {
-          @apply h-5 !important;
-        }
-
-        .ProseMirror-icon {
-          @apply p-1 w-3 h-3 text-n-slate-12 dark:text-n-slate-12 !important;
-        }
-      }
       .ProseMirror.ProseMirror-woot-style {
         p {
           @apply first:mt-0 !important;