cmd/eval: pass parsed input into rego package for wasm target if present (#3669)

This was introduced in #3624: turns out the eval command's code only
passed parsedInput into the rego package, and that only looked at
rawInput when feeding it into the wasm engine.

The approach taken here is to make the rego package more robust: It
should do the right thing if parsedInput is provided for an eval
under the wasm target: the parsing work was already done, let's not
dischard it.

Fixes #3666.

Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>