flutter-engine: export HOME for dart

Set the HOME variable to point to the WORKDIR to prevent any issues with
dart runtime configs and cache. Required because of:

dart-lang/sdk#41560

Signed-off-by: Randolph Sapp <rs@ti.com>

recipes-graphics/flutter-engine/flutter-engine_git.bb

@@ -224,6 +224,8 @@ do_configure() {
 do_configure[depends] += "depot-tools-native:do_populate_sysroot"
 
 do_compile() {
+    # required for dart: https://github.com/dart-lang/sdk/issues/41560
+    export HOME=${WORKDIR}
 
     FLUTTER_RUNTIME_MODES="${@bb.utils.filter('PACKAGECONFIG', 'debug profile release jit_release', d)}"
     bbnote "FLUTTER_RUNTIME_MODES=${FLUTTER_RUNTIME_MODES}"