chore(runway): cherry-pick chore(ci): enable RC rolling builds (#28687)

- chore(ci): enable RC rolling builds (#28680)

## Description

Adds **rolling builds** for the **Auto RC builds** workflow
(`.github/workflows/build-rc-auto.yml`) by setting a **concurrency
group** on `github.workflow` + `github.ref` with **`cancel-in-progress:
true`**.

When a new run starts for a given `release/*` branch, any **queued or
in-progress** run of the same workflow for that branch is **cancelled**,
so only the latest push is built. This mirrors Bitrise-style rolling
builds and avoids piling up redundant RC builds when the release branch
gets several commits in a short time.

## Changelog

CHANGELOG entry: null

internal CI behavior only.

## Related issues

Fix: https://consensyssoftware.atlassian.net/browse/MCWP-518

## Manual testing steps

N/A — CI-only change. Verify by pushing multiple commits quickly to a
labeled release PR and confirming older Auto RC workflow runs are
cancelled while the newest run proceeds.
[0805e78](0805e78)

Co-authored-by: João Loureiro <175489935+joaoloureirop@users.noreply.github.com>

Author: runway-github[bot]

.github/workflows/build-rc-auto.yml

@@ -4,6 +4,10 @@
 # It runs on every commit pushed to a release branch, but only when the release PR
 # has the 'auto-rc-builds' label.
 #
+# Rolling builds: when a new run starts for the same release branch, any queued or
+# in-progress run of this workflow for that branch is cancelled (same behavior as
+# Bitrise “Rolling builds” / “Abort running builds” for one branch + one workflow).
+#
 # Builds are triggered via the Runway OTA/build pipeline (runway-ota-build-core.yml):
 # - iOS runs first and performs the version bump.
 # - Android runs after, skipping the version bump (already done by iOS).
@@ -16,6 +20,10 @@ on:
     branches:
       - 'release/*'
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: write
   pull-requests: write