Expose '--force-sparse-encoding' flag for 'optimize' and 'convert' commands.

This allows to use sparse encoding for APKs that do not specify minSdk
version inside. This is common for split APKs generated by bundletool
when Android App Bundle (AAB) is split into multiple APKs.

Bug: b/223394605
Test: TableFlattener_test
Change-Id: I2a99a611f855cffbcea20018d869e1eb54d1b3d5
diff --git a/tools/aapt2/cmd/Convert.cpp b/tools/aapt2/cmd/Convert.cpp
index cf58f98..aeedf8b 100644
--- a/tools/aapt2/cmd/Convert.cpp
+++ b/tools/aapt2/cmd/Convert.cpp
@@ -395,6 +395,12 @@
                                     << output_format_.value());
     return 1;
   }
+  if (enable_sparse_encoding_) {
+    table_flattener_options_.sparse_entries = SparseEntriesMode::Enabled;
+  }
+  if (force_sparse_encoding_) {
+    table_flattener_options_.sparse_entries = SparseEntriesMode::Forced;
+  }
 
   return Convert(&context, apk.get(), writer.get(), format, table_flattener_options_,
                  xml_flattener_options_);