### ImageMagick version

 7.1.0-61

### Operating system

Windows

### Operating system, version and so on

Windows 11

### Description

When reducing colors, sometimes the number of colors may be reduced below the number specified, resulting in unnecessary loss of color quality. I probably had at least 1 situation when the number of colors in the input image is less than the number of colors to reduce to but colors were removed anyway. Also see related issue #5926.

### Steps to Reproduce

`magick filename.png -colors 256` (use the image below)
Ideally, the result should have exactly 256 colors, but for that particular image the result only has 210 colors. 

### Images

![r](https://user-images.githubusercontent.com/53478680/231358901-4eadb092-f68b-47d6-b633-cc2f0b417190.png)
This image contains 257 colors.
-colors method issues
This is a GitHub Issue
repo:ImageMagick
owner:ImageMagick
Title : -colors method issues
Issue date:

--- start body ---
### ImageMagick version

 7.1.0-61

### Operating system

Windows

### Operating system, version and so on

Windows 11

### Description

When reducing colors, sometimes the number of colors may be reduced below the number specified, resulting in unnecessary loss of color quality. I probably had at least 1 situation when the number of colors in the input image is less than the number of colors to reduce to but colors were removed anyway. Also see related issue #5926.

### Steps to Reproduce

`magick filename.png -colors 256` (use the image below)
Ideally, the result should have exactly 256 colors, but for that particular image the result only has 210 colors. 

### Images

![r](https://user-images.githubusercontent.com/53478680/231358901-4eadb092-f68b-47d6-b633-cc2f0b417190.png)
This image contains 257 colors.
--- end body ---
