fix: update workspace creation modal phrasing for credit pool clarity (#9811)

## Summary

Update workspace creation modal copy to clarify that creating a
workspace establishes a **new** credit pool, rather than sharing from
the owner's existing credits.

## Changes

- **What**: Changed i18n message from "Workspaces let members share a
single credits pool" to "Workspaces create a new credit pool that can be
shared among members"

## Review Focus

Copy change only — single i18n string update in
`src/locales/en/main.json`.

Fixes COM-16521

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9811-fix-update-workspace-creation-modal-phrasing-for-credit-pool-clarity-3216d73d36508186850ac5a8ad97461d)
by [Unito](https://www.unito.io)

src/locales/en/main.json

@@ -2511,7 +2511,7 @@
     },
     "createWorkspaceDialog": {
       "title": "Create a new workspace",
-      "message": "Workspaces let members share a single credits pool. You'll become the owner after creating this.",
+      "message": "Workspaces create a new credit pool that can be shared among members. You'll become the owner after creating this.",
       "nameLabel": "Workspace name*",
       "namePlaceholder": "Enter workspace name",
       "create": "Create"