CI: Call for Grafana version on demand - remove need for version.json (#54638)

* Remove need for version.json

* Fix lint

* log.Info -> fmt.Print

* Add back tests

* Remove non-used file

* Fix lint

* Update grabpl version to v3.0.6

pkg/build/config/version.go

@@ -2,10 +2,7 @@ package config
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
-	"io"
-	"log"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -57,40 +54,6 @@ func (md *Metadata) GetReleaseMode() (ReleaseMode, error) {
 // than the way it will be built in 'main'
 type VersionMap map[VersionMode]Version
 
-// GetMetadata attempts to read the JSON file located at 'path' and decode it as a Metadata{} type.
-// If the provided path does not exist, then an error is not returned. Instead, an empty metadata is returned with no error.
-func GetMetadata(path string) (*Metadata, error) {
-	if _, err := os.Stat(path); err != nil {
-		if errors.Is(err, os.ErrNotExist) {
-			return &Metadata{}, nil
-		}
-		return nil, err
-	}
-	// Ignore gosec G304 as this function is only used in the build process.
-	//nolint:gosec
-	file, err := os.Open(path)
-	if err != nil {
-		return nil, err
-	}
-	defer func() {
-		if err := file.Close(); err != nil {
-			log.Printf("error closing file at '%s': %s", path, err.Error())
-		}
-	}()
-
-	return DecodeMetadata(file)
-}
-
-// DecodeMetadata decodes the data in the io.Reader 'r' as Metadata.
-func DecodeMetadata(r io.Reader) (*Metadata, error) {
-	m := &Metadata{}
-	if err := json.NewDecoder(r).Decode(m); err != nil {
-		return nil, err
-	}
-
-	return m, nil
-}
-
 // GetVersions reads the embedded config.json and decodes it.
 func GetVersion(mode VersionMode) (*Version, error) {
 	if v, ok := Versions[mode]; ok {