Default image builder: Creates HOME if it does not exists

[thomasjpfan]

Why are the changes needed?

For some images, the $HOME directory does not exists yet. With this PR, it gets created. For example, if one specifies the normal flyte base image, it'll fail to build.

from flytekit import ImageSpec, task

image = ImageSpec(
    base_image="ghcr.io/flyteorg/flytekit:py3.12-1.13.0",
    packages=["pandas==2.2.2"],
    registry="localhost:30000",
)

@task(container_image=image)
def get():
    return

Note that the default image builder does not use the python environment from the base_image and creates its own Python environment.

How was this patch tested?

Unit test was updated in this PR.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.81%. Comparing base (a6a8651) to head (eee9eef).
Report is 5 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2562      +/-   ##
==========================================
+ Coverage   76.27%   80.81%   +4.53%     
==========================================
  Files         183      209      +26     
  Lines       18716    19964    +1248     
  Branches     3694     3695       +1     
==========================================
+ Hits        14275    16133    +1858     
+ Misses       3804     3175     -629     
- Partials      637      656      +19     

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