roblox_bot_file: hide file tests behind feature flag

Files are missing from git tree which causes `cargo test` run on the repository root to fail.  This change means that all tests from all modules now pass.

lib/roblox_bot_file/Cargo.toml

@@ -6,3 +6,6 @@ edition = "2021"
 [dependencies]
 binrw = "0.14.1"
 bitflags = "2.6.0"
+
+[features]
+test=[]

lib/roblox_bot_file/src/tests.rs

@@ -1,3 +1,5 @@
+#[cfg(feature="test")]
+mod file{
 use crate::v0::TimedBlockId;
 
 #[test]
@@ -39,3 +41,4 @@ fn _2()->Result<(),crate::v0::Error>{
 
 	Ok(())
 }
+}