[chore][component] Minor stylistic updates to component.ID (open-telemetry#13543)

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#### Description

Minor stylistic things I noticed while looking at `component.ID`:

* We should assert the interfaces it implements.
* We don't use the "result parameters"/named return parameters in
`MarshalText`. I'm more ambivalent on this one, but I was a bit
surprised to see them when they're not used. I can see reasons to keep
them as well if we'd prefer.

Author: evan-bradley

component/identifiable.go

@@ -4,6 +4,7 @@
 package component // import "go.opentelemetry.io/collector/component"
 
 import (
+	"encoding"
 	"errors"
 	"fmt"
 	"regexp"
@@ -71,6 +72,12 @@ func MustNewType(strType string) Type {
 	return ty
 }
 
+var (
+	_ fmt.Stringer             = ID{}
+	_ encoding.TextMarshaler   = ID{}
+	_ encoding.TextUnmarshaler = (*ID)(nil)
+)
+
 // ID represents the identity for a component. It combines two values:
 // * type - the Type of the component.
 // * name - the name of that component.
@@ -116,7 +123,7 @@ func (id ID) Name() string {
 
 // MarshalText implements the encoding.TextMarshaler interface.
 // This marshals the type and name as one string in the config.
-func (id ID) MarshalText() (text []byte, err error) {
+func (id ID) MarshalText() ([]byte, error) {
 	return []byte(id.String()), nil
 }