Add serde_json dependency to opentelemetry-proto when with-serde feature is enabled

Co-authored-by: cijothomas <[email protected]>

Author: Copilot

opentelemetry-proto/Cargo.toml

@@ -49,7 +49,7 @@ testing = ["opentelemetry/testing"]
 # add ons
 internal-logs = ["opentelemetry/internal-logs"]
 with-schemars = ["schemars"]
-with-serde = ["serde", "const-hex", "base64"]
+with-serde = ["serde", "const-hex", "base64", "serde_json"]
 
 [dependencies]
 tonic = { workspace = true, optional = true, features = ["codegen", "prost"] }
@@ -58,6 +58,7 @@ opentelemetry = { workspace = true }
 opentelemetry_sdk = { workspace = true }
 schemars = { workspace = true, optional = true }
 serde = { workspace = true, optional = true, features = ["serde_derive"] }
+serde_json = { workspace = true, optional = true }
 const-hex = { workspace = true, optional = true }
 base64 = { workspace = true, optional = true }