Handle multiple PRs and contributors in changelog generation + Simplify CR handling

[Musholic]

Description of the problem being solved:

This simplifies the handling of the \r character by removing them all at the beginning and adding them back at the end (so that we don't have to care about them in the rest of the process).

It also adds the support of multiple PRs and contributors (when generating a release with a provided releaseNoteUrl).

For example, with this in the draft release:

* Handle multiple PRs and contributors in changelog generation + Simplify CR handling by (@Musholic, @LocalIdentity) in (https://github.com/Musholic/PathOfBuilding-PoE2/pull/12, https://github.com/Musholic/PathOfBuilding-PoE2/pull/11)
* Handle multiple PRs and contributors in changelog generation + Simplify CR handling by @Musholic, @LocalIdentity in https://github.com/Musholic/PathOfBuilding-PoE2/pull/12, https://github.com/Musholic/PathOfBuilding-PoE2/pull/11
* Handle multiple PRs and contributors in changelog generation + Simplify CR handling by @Musholic in https://github.com/Musholic/PathOfBuilding-PoE2/pull/12

It produces this commit: Musholic@2d62e1e

For the beta release it produces this commit: Musholic@a77187e

• Should it handle short #PR in draft changelog? like in:

* Handle multiple PRs and contributors in changelog generation + Simplify CR handling by (@Musholic, @LocalIdentity) in (#12, #11)

[Musholic]

I've added the logic to prevent the generation of empty changelogs for beta version, it now correctly produces an empty commit (Musholic@b312647, workflow: https://github.com/Musholic/PathOfBuilding-PoE2/actions/runs/17761574913/job/50475345619)

I checked that it did not break normal release changelog generation (Musholic@16fc7f9)

I also checked it did not break normal beta release changelog generation (Musholic@6c06720)