This commit update the RBE configuration to use `bes_instance_name` instead
of `project_id`, which got renamed [in Bazel 5.1][1]. Doing so avoids several warnings
in the CI output.

[1]: https://github.com/bazelbuild/bazel/commit/2b48c6b9a447756fcb3295b8a75899b96efa7fd4

PR Close #51696