CI: Skip the CI Builds that don't match the Board Label

[lupyuen]

Summary

This PR extends the CI Build Rules to eliminate more unnecessary builds. We use the Board Label for PRs:

• Previously: "Arch: arm" will build only arm-01 to arm-14
• Now: "Board: arm" will also build arm-01 to arm-14
• This applies only to Simple PRs: One Arch Label + One Board Label + One Size Label, like "Arch: arm, Board: arm, Size: L"
• If Arch Label and Board Label are both present: They must be the same. Otherwise All Targets shall be built.
• Works with Arm32, Arm64, RISC-V, Simulator, x86_64 and Xtensa

The updated code is explained here: apache#13775

Impact

Simple PRs targeting One Single Board and/or Arch shall complete the CI Build a lot quicker now.

The Updated CI Workflow shall be synced to nuttx-apps repo in the next PR.

Testing

We tested by creating PRs with Arch and Board Labels:

• "Board: arm" builds arm-01 to arm-14
• "Board: arm, Arch: arm" also builds arm-01 to arm-14
• "Board: risc-v, Arch: arm" will build All Targets (because the labels don't match)