[chore] update otel libraries (#3740)

* chore: update otel dependencies

* refactor: combine tracing & metrics in observability package

* chore: update example tracing compose file

vendor/go.opentelemetry.io/otel/sdk/metric/internal/x/README.md

@@ -10,6 +10,7 @@ See the [Compatibility and Stability](#compatibility-and-stability) section for
 
 - [Cardinality Limit](#cardinality-limit)
 - [Exemplars](#exemplars)
+- [Instrument Enabled](#instrument-enabled)
 
 ### Cardinality Limit
 
@@ -102,6 +103,24 @@ Revert to the default exemplar filter (`"trace_based"`)
 unset OTEL_METRICS_EXEMPLAR_FILTER
 ```
 
+### Instrument Enabled
+
+To help users avoid performing computationally expensive operations when recording measurements, synchronous instruments provide an `Enabled` method.
+
+#### Examples
+
+The following code shows an example of how to check if an instrument implements the `EnabledInstrument` interface before using the `Enabled` function to avoid doing an expensive computation:
+
+```go
+type enabledInstrument interface { Enabled(context.Context) bool }
+
+ctr, err := m.Int64Counter("expensive-counter")
+c, ok := ctr.(enabledInstrument)
+if !ok || c.Enabled(context.Background()) {
+    c.Add(expensiveComputation())
+}
+```
+
 ## Compatibility and Stability
 
 Experimental features do not fall within the scope of the OpenTelemetry Go versioning and stability [policy](../../../../VERSIONING.md).

vendor/go.opentelemetry.io/otel/sdk/metric/internal/x/x.go

@@ -8,41 +8,26 @@
 package x // import "go.opentelemetry.io/otel/sdk/metric/internal/x"
 
 import (
+	"context"
 	"os"
 	"strconv"
-	"strings"
 )
 
-var (
-	// Exemplars is an experimental feature flag that defines if exemplars
-	// should be recorded for metric data-points.
-	//
-	// To enable this feature set the OTEL_GO_X_EXEMPLAR environment variable
-	// to the case-insensitive string value of "true" (i.e. "True" and "TRUE"
-	// will also enable this).
-	Exemplars = newFeature("EXEMPLAR", func(v string) (string, bool) {
-		if strings.ToLower(v) == "true" {
-			return v, true
-		}
-		return "", false
-	})
-
-	// CardinalityLimit is an experimental feature flag that defines if
-	// cardinality limits should be applied to the recorded metric data-points.
-	//
-	// To enable this feature set the OTEL_GO_X_CARDINALITY_LIMIT environment
-	// variable to the integer limit value you want to use.
-	//
-	// Setting OTEL_GO_X_CARDINALITY_LIMIT to a value less than or equal to 0
-	// will disable the cardinality limits.
-	CardinalityLimit = newFeature("CARDINALITY_LIMIT", func(v string) (int, bool) {
-		n, err := strconv.Atoi(v)
-		if err != nil {
-			return 0, false
-		}
-		return n, true
-	})
-)
+// CardinalityLimit is an experimental feature flag that defines if
+// cardinality limits should be applied to the recorded metric data-points.
+//
+// To enable this feature set the OTEL_GO_X_CARDINALITY_LIMIT environment
+// variable to the integer limit value you want to use.
+//
+// Setting OTEL_GO_X_CARDINALITY_LIMIT to a value less than or equal to 0
+// will disable the cardinality limits.
+var CardinalityLimit = newFeature("CARDINALITY_LIMIT", func(v string) (int, bool) {
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		return 0, false
+	}
+	return n, true
+})
 
 // Feature is an experimental feature control flag. It provides a uniform way
 // to interact with these feature flags and parse their values.
@@ -83,3 +68,14 @@ func (f Feature[T]) Enabled() bool {
 	_, ok := f.Lookup()
 	return ok
 }
+
+// EnabledInstrument informs whether the instrument is enabled.
+//
+// EnabledInstrument interface is implemented by synchronous instruments.
+type EnabledInstrument interface {
+	// Enabled returns whether the instrument will process measurements for the given context.
+	//
+	// This function can be used in places where measuring an instrument
+	// would result in computationally expensive operations.
+	Enabled(context.Context) bool
+}