Upload method support for Nucleo WL55JC, fix common tickers test for STM32

[multiplemonomials]

Summary of changes

This PR adds upload method support for STM32WL. I picked up one of these boards a while back, and finally this week had time to try it out!

I also noticed that the common tickers LP ticker rollover test was failing for this target, and did some digging into what was going on. Turns out that the code was fine, and this was just my stricter test failing due to a limitation of this target's HW (+ also this behavior was not documented well).

Impact of changes

Migration actions required

Documentation

Marked STM32WL as tested! mbed-ce/mbed-ce-dot-dev@6d80c9c

---

Pull request type

[] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[X] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

---

Test results

[] No Tests required for this change (E.g docs only update)
[] Covered by existing mbed-os tests (Greentea or Unittest)
[X] Tests / results supplied as part of this PR

Did a greentea run, and everything passes!

100% tests passed, 0 tests failed out of 120

Total Test time (real) = 562.94 sec

---