Search child folders of subprojects parent folder for subprojects

Previously, the subprojects parent folder was searched for subprojects. Due to the recursive search setting, that still
found library example sketches (after unnecessarily checking the examples folder itself for a sketch). However, the
subproject search of platform bundled libraries is not recursive (because the libraries must be directly under the
libraries folder), meaning these subprojects were not discovered.

Author: per1234

project/project.go

@@ -120,7 +120,7 @@ func findProjectsUnderPath(targetPath *paths.Path, projectTypeFilter projecttype
 // findSubprojects finds subprojects of the given project.
 // For example, the subprojects of a library are its example sketches.
 func findSubprojects(superproject Type, apexSuperprojectType projecttype.Type) []Type {
-	subprojectFolderNames := []string{}
+	subprojectsFolderNames := []string{}
 	var subProjectType projecttype.Type
 	var searchPathsRecursively bool
 
@@ -130,11 +130,11 @@ func findSubprojects(superproject Type, apexSuperprojectType projecttype.Type) [
 		// Sketches don't have subprojects
 		return nil
 	case projecttype.Library:
-		subprojectFolderNames = append(subprojectFolderNames, library.ExamplesFolderSupportedNames()...)
+		subprojectsFolderNames = append(subprojectsFolderNames, library.ExamplesFolderSupportedNames()...)
 		subProjectType = projecttype.Sketch
 		searchPathsRecursively = true // Examples sketches can be under nested subfolders
 	case projecttype.Platform:
-		subprojectFolderNames = append(subprojectFolderNames, platform.BundledLibrariesFolderNames()...)
+		subprojectsFolderNames = append(subprojectsFolderNames, platform.BundledLibrariesFolderNames()...)
 		subProjectType = projecttype.Library
 		searchPathsRecursively = false // Bundled libraries must be in the root of the libraries folder
 	case projecttype.PackageIndex:
@@ -146,9 +146,19 @@ func findSubprojects(superproject Type, apexSuperprojectType projecttype.Type) [
 
 	// Search the subproject paths for projects.
 	var immediateSubprojects []Type
-	for _, subprojectFolderName := range subprojectFolderNames {
-		subprojectPath := superproject.Path.Join(subprojectFolderName)
-		immediateSubprojects = append(immediateSubprojects, findProjectsUnderPath(subprojectPath, subProjectType, searchPathsRecursively)...)
+	for _, subprojectsFolderName := range subprojectsFolderNames {
+		subprojectsPath := superproject.Path.Join(subprojectsFolderName)
+		if subprojectsPath.Exist() {
+			directoryListing, err := subprojectsPath.ReadDir()
+			if err != nil {
+				panic(err)
+			}
+			directoryListing.FilterDirs()
+
+			for _, subprojectPath := range directoryListing {
+				immediateSubprojects = append(immediateSubprojects, findProjectsUnderPath(subprojectPath, subProjectType, searchPathsRecursively)...)
+			}
+		}
 	}
 
 	var allSubprojects []Type