fix: add emoji slash entry and tighten emoji picker modal width

[AlexAndBear]

Description

This bugfix addresses two editor UX issues around emoji insertion:

• Adds the missing emoji insert entry (with icon) to slash commands.
• Fixes emoji picker modal sizing so the modal follows picker dimensions instead of rendering wider than the picker.
• Applies the modal-width behavior consistently, including the Set Space Icon flow.

Related Issue

• Fixes n/a (no tracking issue provided)

How Has This Been Tested?

• test environment: local dev environment on macOS
• test case 1: pnpm check:types
• test case 2: pnpm test:unit --run packages/web-pkg/tests/unit/editor/composables/useEditorActions.spec.ts packages/web-pkg/tests/unit/editor/composables/useTextEditor.spec.ts packages/web-pkg/tests/unit/editor/strategies/html.spec.ts packages/web-pkg/tests/unit/editor/strategies/markdown.spec.ts packages/web-pkg/tests/unit/editor/strategies/tiptapJson.spec.ts packages/web-app-files/tests/unit/composables/actions/spaces/useSpaceActionsSetIcon.spec.ts

Types of changes

• Bugfix
• Enhancement (a change that does not break existing code or deployments)
• Breaking change (a modification that affects current functionality)
• Technical debt (addressing code that needs refactoring or improvements)
• Tests (adding or improving tests)
• Documentation (updates or additions to documentation)
• Maintenance (like dependency updates or tooling adjustments)