clang-tidy : disable warning about performance enum size (#16127)

Disable 'performance-enum-size' checking:

Enum 'llama_token_type' uses a larger base type ('unsigned int', size: 4 bytes)
than necessary for its value set, consider using 'std::uint8_t' (1 byte) as the
base type to reduce its size.

.clang-tidy

@@ -17,6 +17,7 @@ Checks: >
     clang-analyzer-*,
     -clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling,
     performance-*,
+    -performance-enum-size,
     portability-*,
     -portability-simd-intrinsics,
     misc-*,