Update collect-assets to download kai assets from main branch / latest CI workflows

[sjd78]

Currently the collect-assets script only supports downloading kai binaries from released assets.

Two changes are needed.

First, to better support development cycles, the collect-assets scripts need to be able to download the kai assets from a workflow run on the more recent commit on the main branch of the kai repository.

• The kai build workflow runs with assets attached on the main branch: https://github.com/konveyor/kai/actions/workflows/build-and-push-binaries.yml?query=branch%3Amain+is%3Asuccess
• A recent run with the artifacts attached: https://github.com/konveyor/kai/actions/runs/12775086839

Second, the current kai build will also include some of the assets we currently static keep in the repo under assets/. What ever assets can be downloaded from the kai builds should be and the local copy removed.

[sjd78]

I just noticed in https://github.com/konveyor/editor-extensions/actions/runs/12893802399/job/35951338229?pr=233#step:5:112 that if a release tag isn't found, the packaging process doesn't fail! Not finding a release need to be a fail.

Edit: Opened #235 to cover this.

[sjd78]

Note: #194 takes care of the first change.

Followup issues are required to

1. replace static assets with downloading those assets packaged with kai (jdtls, jdtls bundles, seed rulesets, maven index file)
2. make the collection/download fail if the target release/workflow run is not available

Edit: Opened #234 to cover this.