Add missing LICENSE.txt file to container wheel build environment

[johnthagen]

Fix error in container image build which is validated in newer versions of uv by COPYing LICENSE.txt file into the build container image.

 > [python_builder 8/8] RUN uv sync --locked --no-default-groups --no-editable:
0.286 Resolved 70 packages in 0.83ms
0.287    Building fact @ file:///src
0.290   × Failed to build `fact @ file:///src`
0.290   ├─▶ Invalid pyproject.toml
0.290   ╰─▶ `project.license-files` glob `LICENSE*` did not match any files
------