text: Title: `gc --not-in-remote`: misleading warning message
  Body: # Bug Report
  
  ## Description
  
  The warning message printed when using the `--not-in-remote` flag appears to be incorrect. The behavior of the flag appears correct (consistent with the documentation); the warning message is not consistent with behavior or documentation.
  
  ### Reproduce
  
  `dvc gc --workspace --not-in-remote`
  
  Prints the following warning:
  
  ```
  WARNING: This will remove all cache except items used in the workspace that are present in the DVC remote of the current repo.
  Are you sure you want to proceed? [y/n]: 
  ```
  
  The actual behavior for this command is to keep only the local cache items that are: a) referenced in the current workspace, and b) not present in the remote.
  
  ### Expected
  
  The warning message should read, perhaps,
  
  ```
  WARNING: This will remove all cache except items used in the workspace that are not present in the DVC remote of the current repo.
  Are you sure you want to proceed? [y/n]: 
  ```
  
  (That is, just adding the word "not".)
  
  ### Environment information
  
  
  **Output of `dvc doctor`:**
  
  ```console
  $ dvc doctor
  ```
  
  ```
  DVC version: 3.55.2 (pip)
  -------------------------
  Platform: Python 3.12.7 on macOS-15.0.1-x86_64-i386-64bit
  Subprojects:
  	dvc_data = 3.16.6
  	dvc_objects = 5.1.0
  	dvc_render = 1.0.2
  	dvc_task = 0.40.2
  	scmrepo = 3.3.8
  Supports:
  	http (aiohttp = 3.10.10, aiohttp-retry = 2.8.3),
  	https (aiohttp = 3.10.10, aiohttp-retry = 2.8.3),
  	s3 (s3fs = 2024.9.0, boto3 = 1.35.36)
  Config:
  	Global: /Users/dan/Library/Application Support/dvc
  	System: /Library/Application Support/dvc
  Cache types: reflink, hardlink, symlink
  Cache directory: apfs on /dev/disk1s1s1
  Caches: local
  Remotes: s3
  Workspace directory: apfs on /dev/disk1s1s1
  Repo: dvc, git
  Repo.site_cache_dir: /Library/Caches/dvc/repo/a60ba71a9b85f3c8d2c283884465924b
  ```
  