Fix: ComponentParamCollection needs numItems and length property

[galaddirie]

fixes #112

Observed this issue when trying to iterate over the properties of a component. I noticed I could access properties through indexing but when trying to access the length of the collection, we received a linting error but the code works at run time. Property 'numItems' does not exist on type 'ComponentParamCollection'.ts(2339)

const seq = app.project.activeSequence;
  const tracks = seq.getSelection();
  for (let track of tracks) {
      let components: ComponentCollection = track.components;
      for (let i = 0; i < components.numItems; i++) {
          const comp = components[i];
          comp.properties[0]
          for (let j = 0; j < comp.properties.numItems; j++) { // !THE ISSUE
              // numItems and length is not defined in ComponentPropertiesCollection, but this exists

I noticed that the numItems and length properties were used in the codebase but weren't defined like other Collection types

all this fix does is set the properties length and numItems

[justintaylor-dev]

looks good, thanks