Double free in tool_cfgable.c

### I did this

CheckScope found a double free bug in tool_cfgable.c.
At lines 104–105 and 187–188, config->proto_str and config->proto_redir_str are each freed twice.

### I expected the following

merge request: https://github.com/curl/curl/pull/19214

### curl/libcurl version

master:latest

### operating system

Ubuntu