Support emitting traces behind feature flag (#2576)

* Let logging be skippable so user can handle logger()

* Add changes file

* changes meta info

* Update documentation

* Support emitting to tracing behind feature flag

* typo

* rename key_values => kv

* changes file

* Remove rebase skip-logger

* fix format

plugins/log/Cargo.toml

@@ -33,6 +33,8 @@ byte-unit = "5"
 log = { workspace = true, features = ["kv_unstable"] }
 time = { version = "0.3", features = ["formatting", "local-offset"] }
 fern = "0.7"
+tracing = { workspace = true, optional = true }
+
 
 [target."cfg(target_os = \"android\")".dependencies]
 android_logger = "0.15"
@@ -47,3 +49,4 @@ objc2-foundation = { version = "0.3", default-features = false, features = [
 
 [features]
 colored = ["fern/colored"]
+tracing = ["dep:tracing"]