Update the minimum version of databricks-labs-pytester to 0.7.2 (#4028)

The [just
released](https://github.com/databrickslabs/pytester/releases/tag/v0.7.2)
version of `pytester` includes a fix for a breaking change that was
introduced by Databricks SDK 0.51: older versions of pytester will fail
to import if the new Databricks SDK is present.

This PR updates the test dependency to the version that was just
released:

- This is mainly informational in terms of the breaking change: it
doesn't affect user installs, and fresh development environments will
probably pick up the newer version anyway.
- The existing specified version is probably wrong: since 0.3.0 we've
introduced things in pytester that `ucx` requires, but the dependency
was not updated to reflect this.

Author: asnare

pyproject.toml

@@ -78,7 +78,7 @@ dependencies = [
     "pylint~=3.3.1",
     "pylint-pytest==2.0.0a0",
     "databricks-labs-pylint~=0.5",
-    "databricks-labs-pytester>=0.3.0",
+    "databricks-labs-pytester>=0.7.2",
     "pytest~=8.3.3",
     "pytest-cov~=4.1.0",
     "pytest-mock~=3.14.0",