Re: [meta-virtualization][RFC][PATCH 1/5] vcontainer-bbmask.inc: add python3-pexpect,-ptyprocess

Thanks Tim. I'm taking 2/5 through 5/5 directly (verified 2/5 against
image-oci.bbclass — the auto-fold of OCI_LAYERS `packages:` entries
into IMAGE_INSTALL at line ~389 is exactly the duplication this drops,
so it's a clean removal). 3/5's added deps all trace to concrete
failures documented in 5/5, which is a great artifact.

One question before I take this one:

The commit says python3-pexpect is needed "during run-time testing
with the bitbake-setup workflow." What in the built container actually
imports/exec's pexpect at runtime? If it's the vcontainer test suite
driving the container from outside, pexpect belongs on the test host,
not baked into the image. If it's something inside the container —
bitbake-setup itself, a Yocto tool, or a test harness that runs
in-container — that's legitimate, but a one-line note in the commit
message naming the caller would help future readers understand why
we're carving a hole in the meta-python mask.

If it's just needed for our own vcontainer test runner and not by
anything the container itself invokes, I'd rather leave the meta-python
mask intact and put pexpect on the host that runs the tests.

Bruce