chore: set helm buildflags the way Zarf does

[catsby]

Description

Without setting these buildflags, some uds zarf commands could produce different results than directly using zarf of the same version. See details for example.

❯ uds version               
v0.20.0

❯ uds zarf version                    
v0.45.0

❯ zarf version                    
v0.45.0

❯ uds zarf dev find-images -f upstream
[... omitted things ...]
 NOTE  Using build directory .
     [... omitted things ...]
     ERROR:  unable to find images: could not render the Helm template for [some chart]: error
             generating helm chart template: chart requires kubeVersion: >=1.24.0-0 which is incompatible with
             Kubernetes v1.20.0

❯ zarf dev find-images -f upstream    
[... omitted things ...]
 NOTE  Using build directory .
  [... omitted things ...]
components:

  - name: [some chart]
    images:
      - alpine
      - nats:2.10.19-alpine
      - [other images]

In this PR we add the necessary variables and buildflags to get the correct results in a similar manner to how Zarf does.

❯ uds zarf dev find-images -f upstream    
[... omitted things ...]
 NOTE  Using build directory .
  [... omitted things ...]
components:

  - name: [some chart]
    images:
      - alpine
      - nats:2.10.19-alpine
      - [other images]

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Test, docs, adr added or updated as needed
• Contributor Guide Steps followed