endpoint: rename GetMetadataValue to GetPropertyValue

During the PR review for d735c50 it was suggested to change the
field name from endpoint.Metadata to endpoint.Properties. Unfortunately,
this method was missed during the renaming and this commit sets the
right name to it.

Fixes: d735c50 ("introduce 'properties' for endpoints")
Signed-off-by: André Martins <andre@isovalent.com>
Signed-off-by: Gilberto Bertin <jibi@cilium.io>

pkg/endpoint/endpoint.go

@@ -2611,8 +2611,8 @@ func (e *Endpoint) GetCreatedAt() time.Time {
 	return e.createdAt
 }
 
-// GetMetadataValue returns the metadata value for this key.
-func (e *Endpoint) GetMetadataValue(key string) interface{} {
+// GetPropertyValue returns the metadata value for this key.
+func (e *Endpoint) GetPropertyValue(key string) interface{} {
 	e.mutex.RWMutex.RLock()
 	defer e.mutex.RWMutex.RUnlock()
 	return e.properties[key]