…when build sdist (bazel-contrib#2126)

Building sdist results in `Could not find a version that satisfies the
requirement setuptool` this regressed when a fix in parameter handling
got introduced in bazel-contrib#2091.

Before this change the building from sdist when using
`experimental_index_url`
would break because `--no-index` is passed to `pip`. This means that
`pip`
would fail to locate build time dependencies needed for the packages and
would
just not work. In `whl_library` we setup `PYTHONPATH` to have some build
dependencies available (like `setuptools`) and we could use them during
building from `sdist` and to do so we need to add `--no-build-isolation`
flag.
However, for some cases we need to also add other build-time
dependencies (e.g.
`flit_core`) so that the building of the wheel in the `repository_rule`
context
is successfuly. Removing `--no-index` allows `pip` to silently fetch the
needed
build dependencies from PyPI if they are missing and continue with the
build.

This is not a perfect solution, but it does unblock users to use the
`sdist`
distributions with the experimental feature enabled by using
`experimental_index_url` (see bazel-contrib#260 for tracking of the completion).

Fixes bazel-contrib#2118
Fixes bazel-contrib#2152

---------

Co-authored-by: aignas <240938+aignas@users.noreply.github.com>

…rib#2360)

Fixes bazel-contrib#2328.

In bazel-contrib#2126, we discussed and added `--no-build-isolation` to ensure that
sdist builds pulled from rules_python supplied dependencies. An
unanticipated/misunderstood side-effect of this is that pip will no
longer resolve necessary, declared build time dependencies from a
package index. That's a significant point of friction for users, and,
it's much harder to opt-out of the behavior than to opt-in given the
presence of `extra_pip_args`.