mgr/dashboard: fix api test issue with pip

mgr/dashboard: fix api test issue with pip

Fix
```
ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
apache-libcloud 3.5.0 requires requests>=2.26.0, but you have requests 2.25.1 which is incompatible.
Successfully installed CherryPy-13.1.0 PyJWT-2.0.1 Routes-2.4.1 bcrypt-3.1.4 ceph-1.0.0 chardet-4.0.0 cheroot-8.6.0 idna-2.10 jaraco.functools-3.5.0 more-itertools-4.1.0 natsort-8.1.0 portend-3.1.0 pyopenssl-22.0.0 pytz-2022.1 repoze.lru-0.7 requests-2.25.1 tempora-5.0.1
```

Fixes: https://tracker.ceph.com/issues/55060
Signed-off-by: Ernesto Puerta <epuertat@redhat.com>
(cherry picked from commit 2289ad2bc327b0d86916a1c96f4af2967a80c1b9)

 Conflicts:
	src/pybind/mgr/dashboard/constraints.txt
        - keep requests 2.26