[BUGFIX beta] Change preference in positional parameters

[Serabe]

This fixes the behaviour when a positional param conflicts conflicts with
a hash param.

[rwjblue]

I think this should be positionalParams[paramsStartIndex + i].

[Serabe]

No, the for is iterating through the positionalParams array. The paramsStartIndex accounts for the difference if the first parameter is the name of the component (because of the component helper) or a direct invocation. @mixonic got rid of that in #12285 but it is a WIP

[rwjblue]

Gotcha, thank you for explaining.

[rwjblue]

Can you make this an assertion though?

Basically:

assert(`You cannot specify both a positional param (at position ${i}) and the hash argument \`${positionalParams[i]}\`.`, positonalParams[i] in attrs);

Then the tests get updated to something like:

expectAssertion(function() {
  runAppend(view);
}, /The message from above, I am too lazy to type/);

[rwjblue]

Thank you!