Update note on disk removal GUI requirements (#403)

Clarified that in current releases, the GUI only supports removing disks
in RAID 1 configuration. If you do it with other redundant btrfs
profiles, it will leave the pool degraded instead.

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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Documentation**
* Updated guidance on removing storage devices via the GUI to clarify
specific RAID configuration requirements needed to perform this
operation.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: 1JorgeB

docs/unraid-os/using-unraid-to/manage-storage/partials/remove-disk-gui.mdx

@@ -1,7 +1,7 @@
 :::note[Before you start]
 
 - You can only remove one drive at a time using the GUI.
-- Make sure your pool is using a redundant %%RAID|raid%% profile (like %%RAID 1|raid1%% for both data and metadata).
+- The GUI currently only supports removing devices if your pool is set up for %%RAID 1|raid1%%  (for both data and metadata for %%BTRFS|btrfs%%).
 - To check your pool's %%RAID|raid%% level, navigate to the Main tab and click on the pool. Scroll down to the Balance Status section (for %%BTRFS|btrfs%%) or ZFS pool status (for %%ZFS|zfs%%).
 
 :::