/say command fails to apply server message styling when sent from a command block, server console, or RCON, unlike /msg

The bug

Snapshot 22w19a introduced server message styling, which allows messages to be dynamically styled by the server. However, this does not always work consistently. In command blocks, the server console, and from RCON, using the /say command fails to apply this server formatting. When using the /msg command from these interfaces, however, the formatting is properly applied.

How to reproduce

1. Create a server in version 22w19a, with test-rainbow-chat set to true in the server.properties file

2. Start and join the server

3. From the server console, run msg @a hi
   ✔ The message appears properly formatted with rainbow colors

4. From the server console, run say hi
   ❌ The message appears as if it has not been formatted by the server