Generate SpacetimeDBClient.cs in deterministic order

[bfops]

This pertains to C# code generation.

From a Discord comment:

Could we make the SpacetimeDBClient.cs functions/attributes generation follow a deterministic order (like alphabetic order)? I might be wrong, but it seems like there's often changes in that file when there shouldn't be
The spacetimedbclient always cause merge conflicts. It feels like the old way (with more files) was less prone to merge conflicts. Maybe helping with the point aforementioned would help allievate this issue though.

We should investigate creating this file with a deterministic ordering of class members, to reduce changes and therefore merge conflicts.

Definition of Done

• We have investigated what it would take to generate this file deterministically
• If it only takes an hour or two to fix, then we've done that
• Otherwise, we've reported findings and are reassessing/reprioritizing