fix: perfsprint lint violations in opentelemetry logger plugin

[Copilot]

Three perfsprint lint issues in v1/plugins/logger/opentelemetry caused make check to fail. Replaces slow formatting functions with their faster stdlib equivalents.

Changes

• plugin.go — replace fmt.Errorf with errors.New for a static (non-wrapping) error string; add "errors" import
• plugin_test.go — replace fmt.Sprintf("%d", ...) / fmt.Sprintf("%t", ...) with strconv.FormatInt / strconv.FormatBool; add "strconv" import

// before
return fmt.Errorf("OpenTelemetry logger already started")
return fmt.Sprintf("%d", v.IntValue)
return fmt.Sprintf("%t", v.BoolValue)

// after
return errors.New("OpenTelemetry logger already started")
return strconv.FormatInt(v.IntValue, 10)
return strconv.FormatBool(v.BoolValue)