We have an issue in dwg_find_color_index(), which is not working.

The problem is with:
```
BITCODE_BL rgb = 0xff0000;
Dwg_RGB_Palette pal;
pal.r = rgb & 0xff0000;
```
where BITCODE_BL is uint32_t and pal.r is unsigned char and conversion isn't working.
Issue in dwg_find_color_index()
This is a GitHub Issue
repo:libredwg
owner:LibreDWG
Title : Issue in dwg_find_color_index()
Issue date:

--- start body ---
We have an issue in dwg_find_color_index(), which is not working.

The problem is with:
```
BITCODE_BL rgb = 0xff0000;
Dwg_RGB_Palette pal;
pal.r = rgb & 0xff0000;
```
where BITCODE_BL is uint32_t and pal.r is unsigned char and conversion isn't working.
--- end body ---

The issue in dwg_find_color_index() relates to improper type conversion between a 32-bit unsigned integer (BITCODE_BL) and an 8-bit unsigned char (pal.r). This could lead to incorrect color indexing, but it does not present a security vulnerability such as buffer overflow or memory corruption. It is a functional bug rather than a security issue.