During compilation `"--actor-idl"` appears twice

[vporton]

During compilation with -vv flag "--actor-idl" appears twice in an invocation of moc-wrapper:

• "--actor-idl" "/home/porton/Projects/zondirectory2/.dfx/local/canisters/idl/"
• "--actor-idl" ".dfx/local/lsp"

Apparently, this is a bug.

$ dfx --version
dfx 0.20.0-icsystemtest.0+rev256.f4913345