chore: update langchain latest version to 0.3.8

[github-actions]

Update langchain lockfiles and dependency package lockfiles.
This performs the following updates:

1. Some langchain lockfiles use langchain latest. This will update langchain and dependencies.
2. Some langchain lockfiles use a pinned (non-latest) version of langchain, but require the latest version of another package. This will update all such packages.

Checklist

• PR author has checked that all the criteria below are met
• The PR description includes an overview of the change
• The PR description articulates the motivation for the change
• The change includes tests OR the PR description describes a testing strategy
• The PR description notes risks associated with the change, if any
• Newly-added code is easy to change
• The change follows the library release note guidelines
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• Reviewer has checked that all the criteria below are met
• Title is accurate
• All changes are related to the pull request's stated goal
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Newly-added code is easy to change
• Release note makes sense to a user of the library
• If necessary, author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-11-26 18:34:15

Comparing candidate commit f1c5096 in PR branch upgrade-latest-langchain-version with baseline commit 935454a in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 388 metrics, 2 unstable metrics.

[github-actions]

CODEOWNERS have been resolved as:

.riot/requirements/11063bf.txt                                          @DataDog/apm-python
.riot/requirements/16c3b9f.txt                                          @DataDog/apm-python
.riot/requirements/1761cfc.txt                                          @DataDog/apm-python
.riot/requirements/18bc2ac.txt                                          @DataDog/apm-python
.riot/requirements/19f2225.txt                                          @DataDog/apm-python
.riot/requirements/1ec1dbf.txt                                          @DataDog/apm-python
.riot/requirements/457db9b.txt                                          @DataDog/apm-python
.riot/requirements/55a4977.txt                                          @DataDog/apm-python
.riot/requirements/585e779.txt                                          @DataDog/apm-python
.riot/requirements/a311bc2.txt                                          @DataDog/apm-python
.riot/requirements/aa1fe5c.txt                                          @DataDog/apm-python
.riot/requirements/cbbb0eb.txt                                          @DataDog/apm-python
.riot/requirements/cf9bdda.txt                                          @DataDog/apm-python
.riot/requirements/d39d3de.txt                                          @DataDog/apm-python