ci: use pipe mode when calling riot run in run-test-suite [backport 2.0] (#6997)

Backport b406ab1 from #6941 to 2.0.

This switches the output to use pipe mode (which, among other things,
prints every line without wrapping) as a safety mechanism to prevents
reoccurrences of secrets leaking into logs because they were unexpected
wrapped by `riot`'s pretty output.

`riot -v run` is the only place where we show environment variables.

This also adds `scripts/run-test-suite` to the harness suite spec so
that all tests get re-run if the script changes (since that is likely
the desired scenario).

# Testing
## Before

![image](https://github.com/DataDog/dd-trace-py/assets/136473744/5a2d49a2-656b-4ce1-b1dc-1fc999467136)
## After

![image](https://github.com/DataDog/dd-trace-py/assets/136473744/74e00f1f-192d-4e7a-99cd-cbfdb5203b01)

Note that this is an immediate band-aid, not a long-term strategy.

## Checklist

- [x] Change(s) are motivated and described in the PR description.
- [x] Testing strategy is described if automated tests are not included
in the PR.
- [x] Risk is outlined (performance impact, potential for breakage,
maintainability, etc).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] [Library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
are followed. If no release note is required, add label
`changelog/no-changelog`.
- [x] Documentation is included (in-code, generated user docs, [public
corp docs](https://github.com/DataDog/documentation/)).
- [x] Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist

- [x] Title is accurate.
- [x] No unnecessary changes are introduced.
- [x] Description motivates each change.
- [x] Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes unless absolutely necessary.
- [x] Testing strategy adequately addresses listed risk(s).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] Release note makes sense to a user of the library.
- [x] Reviewer has explicitly acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment.
- [x] Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)
- [x] If this PR touches code that signs or publishes builds or
packages, or handles credentials of any kind, I've requested a review
from `@DataDog/security-design-and-guidance`.
- [x] This PR doesn't touch any of that.

Co-authored-by: Romain Komorn <[email protected]>

Author: github-actions[bot]

scripts/run-test-suite

@@ -27,7 +27,7 @@ if ! [[ -v CIRCLECI && $CIRCLE_BRANCH =~ [0-9]\.x ]]; then
 fi
 
 for hash in $RIOT_HASHES; do
-    if ! $DDTEST_CMD riot -v run --exitfirst --pass-env -s $hash $DDTRACE_FLAG $COVERAGE_FLAG; then
+    if ! $DDTEST_CMD riot -P -v run --exitfirst --pass-env -s $hash $DDTRACE_FLAG $COVERAGE_FLAG; then
         if [[ -v CIRCLECI ]]; then
             circleci step halt
         fi

tests/.suitespec.json

@@ -8,6 +8,7 @@
         "$harness": [
             "riotfile.py",
             "scripts/ddtest",
+            "scripts/run-test-suite",
             "hatch.toml",
             "tests/conftest.py",
             "tests/__init__.py",