Embed Filter Data and Improve Compatability

[BrandenAvalonCx]

Two suggested changes here:

Roll back to Abseil version 20250512.1 to maintain compatibility with the Protocol Buffer library.

• Protocol Buffer uses Abseil version 20250512.1, and CMake based builds using both libraries can not combine them as they fetch different versions of Abseil

Move filters to std::spans

• The std::vector BinauralFilters1OAAmbientL() { data ) initialization causes data to be allocated onto the stack
• This in turn causes a stackoverflow in cases where multiple filters are needed. For example, in the Eclipsa project we use multiple binuaural renderers for computing loudness.
• static const unsigned char kDataArray[] embeds the data in the library itself
• std::span initialization uses the data directly rather then performing a copy of the data into a vector on the stack

[yeroro]

I like the direction of eliminating redundant allocation. I just have one ask: can we use absl::Span instead of std::span? Functionally they are almost identical, it's just a preference for code inside Google. Thanks!