fix(model): correct type of fileInfoType in API browse response (fixes #9904) (#9905)

This was broken in the Protobuf refactor. The reason is that with the
previous library, generated types would have a JSON marshalling method
that would automatically return strings for enums. In the current
library you need to use the jsonpb marshaller for that, but these are
hand crafted structs so we can't do that. The easy solution is to just
use strings directly, since this is an API-only type anyway.

lib/model/model.go

@@ -2732,11 +2732,11 @@ func (m *model) Revert(folder string) {
 }
 
 type TreeEntry struct {
-	Name     string                `json:"name"`
-	ModTime  time.Time             `json:"modTime"`
-	Size     int64                 `json:"size"`
-	Type     protocol.FileInfoType `json:"type"`
-	Children []*TreeEntry          `json:"children,omitempty"`
+	Name     string       `json:"name"`
+	ModTime  time.Time    `json:"modTime"`
+	Size     int64        `json:"size"`
+	Type     string       `json:"type"`
+	Children []*TreeEntry `json:"children,omitempty"`
 }
 
 func findByName(slice []*TreeEntry, name string) *TreeEntry {
@@ -2804,7 +2804,7 @@ func (m *model) GlobalDirectoryTree(folder, prefix string, levels int, dirsOnly
 
 		parent.Children = append(parent.Children, &TreeEntry{
 			Name:    base,
-			Type:    f.Type,
+			Type:    f.Type.String(),
 			ModTime: f.ModTime(),
 			Size:    f.FileSize(),
 		})

lib/model/model_test.go

@@ -1729,7 +1729,7 @@ func TestGlobalDirectoryTree(t *testing.T) {
 			Name:    name,
 			ModTime: time.Unix(0x666, 0),
 			Size:    0xa,
-			Type:    protocol.FileInfoTypeFile,
+			Type:    protocol.FileInfoTypeFile.String(),
 		}
 	}
 	d := func(name string, entries ...*TreeEntry) *TreeEntry {
@@ -1737,7 +1737,7 @@ func TestGlobalDirectoryTree(t *testing.T) {
 			Name:     name,
 			ModTime:  time.Unix(0x666, 0),
 			Size:     128,
-			Type:     protocol.FileInfoTypeDirectory,
+			Type:     protocol.FileInfoTypeDirectory.String(),
 			Children: entries,
 		}
 	}