Counter-Strike: Source does not launch

**Game information**
Counter-Strike: Source (native)

**Distribution name and version where applicable**
Fedora 40

**Flatpak info**
Flatpak 1.15.10
default
host

**Problem description**
Counter-Strike: Source crashes on startup with an "Attempt to free invalid pointer" error. This can be worked around by adding `LD_PRELOAD=/app/lib32/libtcmalloc_minimal.so` to the game launch parameters.

It is possible that the following blocklist entry needs an update: https://github.com/flathub/com.valvesoftware.Steam/blob/master/resources/blocklist/counter_strike_source.yml#L8

Related ticket: #1158
Related PR: #1171

/cc @doraskayo

**Does this issue reproduce with native Steam**
Not tested.