Enable lua filter for fluent-bit

[paulmey]

Is your feature request related to a problem? Please describe.
Our org relies on the Lua filter in our fluent-bit config. This filter is disabled in the standard AZL 3.0 package, so currently we maintain our own fork.

Describe the solution you'd like
Remove the -DFLB_LUAJIT=Off configuration from the fluent-bit spec
https://github.com/microsoft/azurelinux/blob/3.0/SPECS/fluent-bit/fluent-bit.spec#L60C1-L60C23

Describe alternatives you've considered
Currently we build our own version of fluent-bit, but we'd like to stop doing that. I've also looked if we can convert our Lua script to other ways of 'log bending', but Lua does seem like the best fit here.

Additional context
Add any other context or screenshots about the feature request here.

[paulmey]

Related on upstream: fluent/fluent-bit#7286
build: use the system provided LuaJIT if found