Revert "Revert "`span`-ification: `mojo::DataPipe[Consumer|Producer]Handle`: New API.""

This reverts commit 96e2562a.

Reason for revert:
LUCI Bisection has identified this change as the culprit of a build failure. See the analysis: https://ci.chromium.org/ui/p/chromium/bisection/compile-analysis/b/8745470788665803729

Sample failed build: https://ci.chromium.org/b/8745470788665803729

If this is a false positive, please report it at http://b.corp.google.com/createIssue?component=1199205&description=Analysis%3A+https%3A%2F%2Fchromium-review.googlesource.com%2Fc%2Fchromium%2Fsrc%2F%2B%2F5619490&format=PLAIN&priority=P3&title=Wrongly+blamed+https%3A%2F%2Fci.chromium.org%2Fui%2Fp%2Fchromium%2Fbisection%2Fcompile-analysis%2Fb%2F8745470788665803729&type=BUG

Original change's description:
> Revert "`span`-ification: `mojo::DataPipe[Consumer|Producer]Handle`: New API."
>
> This reverts commit a23daf4f.
>
> Reason for revert: Causing MSAN issues on https://ci.chromium.org/ui/p/chromium/builders/ci/Linux%20ChromiumOS%20MSan%20Tests/43854/test-results?sortby=&groupby=
>
> Original change's description:
> > `span`-ification: `mojo::DataPipe[Consumer|Producer]Handle`: New API.
> >
> > This CL `span`-ifies the APIs in `mojo/public/cpp/system/data_pipe.h`:
> >
> > * `BeginReadData` and `BeginWriteData` return (via an out parameter)
> >   a `span` instead of returning a ptr+size pair.
> > * `ReadData` and `WriteData` consume a `span` instead of consuming
> >   a ptr+size pair.
> >
> > This CL adds the new APIs + coverts callers under `//mojo`.
> >
> > For more details see the design note here:
> > https://docs.google.com/document/d/1c4NKpXwpQ9MKK1SbJ4C6MvhXI8-KJZ4jq7N4VHTHJoI/edit?usp=sharing
> >
> > Bug: 40284755
> > Change-Id: I70a7fab6e57eb3481305e82dd504de91042fa881
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5598233


> > Auto-Submit: Łukasz Anforowicz <lukasza@chromium.org>
> > Reviewed-by: Daniel Cheng <dcheng@chromium.org>
> > Commit-Queue: Daniel Cheng <dcheng@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#1313022}
>
> Bug: 40284755
> Change-Id: Ifcd3706b24c7842d4bba7065a625b5b3ec9739b4
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5619490
> Owners-Override: Darren Shen <shend@chromium.org>
> Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Auto-Submit: Darren Shen <shend@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1313154}
>

Bug: 40284755
Change-Id: Ia9ddae9679d4f860f26d16a45298984d959b7593
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5619018
Owners-Override: luci-bisection@appspot.gserviceaccount.com <luci-bisection@appspot.gserviceaccount.com>
Commit-Queue: luci-bisection@appspot.gserviceaccount.com <luci-bisection@appspot.gserviceaccount.com>
Bot-Commit: luci-bisection@appspot.gserviceaccount.com <luci-bisection@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1313185}