fix(router): use Json\encode for encoding when sending json responses

[NeoIsRecursive]

I got an issue where my json responses got no output, turns out it was because I had "binary strings" in my object, and since the json_encode didn't throw and I forgot those values existed it took forever for me to debug :3

I figured using the tempest encode function would be better than just adding the throw flag.

[github-actions]

Benchmark Results

Comparison of fix/throw-error-when-recieving-invalid-json against 3.x (8838c1ecb7bf585b2e176d1163cf643c22999b82).

Open to see the benchmark results

No benchmark changes above ±5%.

_{Generated by phpbench against commit aa2651c}