Update to Pex 2.24.3 (#21730)

Highlighted Changelogs:
 * https://github.com/pex-tool/pex/releases/tag/v2.20.4
 * https://github.com/pex-tool/pex/releases/tag/v2.21.0
 * https://github.com/pex-tool/pex/releases/tag/v2.22.0
 * https://github.com/pex-tool/pex/releases/tag/v2.23.0
 * https://github.com/pex-tool/pex/releases/tag/v2.24.0
 * https://github.com/pex-tool/pex/releases/tag/v2.24.1
 * https://github.com/pex-tool/pex/releases/tag/v2.24.2
 * https://github.com/pex-tool/pex/releases/tag/v2.24.3

```
Lockfile diff: 3rdparty/python/user_reqs.lock [python-default]

==                    Upgraded dependencies                     ==

  cryptography                   43.0.3       -->   44.0.0
  deprecated                     1.2.14       -->   1.2.15
  pex                            2.20.3       -->   2.24.3
  pydantic                       1.10.18      -->   1.10.19
  pyjwt                          2.9.0        -->   2.10.1
  six                            1.16.0       -->   1.17.0
  tomli                          2.0.2        -->   2.2.1
  websockets                     13.1         -->   14.1
  wrapt                          1.16.0       -->   1.17.0
```

ref #11167 #18294 for the `pex3 cache` series of commands

3rdparty/python/requirements.txt

@@ -11,7 +11,7 @@ freezegun==1.2.1
 ijson==3.2.3
 libcst==1.4.0
 packaging==21.3
-pex==2.20.3
+pex==2.24.3
 psutil==5.9.8
 # This should be compatible with pytest.py, although it can be looser so that we don't
 # over-constrain pantsbuild.pants.testutil