[1.16] TitaniumFluidInstance source block is replaced from flowing block

[Kenshij]

**Titanium Version: **

**Crashlog If Applicable (Upload to pastebin/gist): **

Bug in com.hrznstudio.titanium.fluid.TitaniumFluidInstance

Source blocks get replaced from a down flowing fluid block, same type.
Industrial-Foregoing mod uses this implementation for its fluid latex. Link
Mentioned there in issue #1324

Confirmed in other Modpacks like The Decursio Project - Expert
industrial-foregoing-1.16.5-3.2.14.7-16
titanium-1.16.5-3.2.8.7-22