Add child build status/link at parent build level

[llxia]

Displaying the child build status and link at the parent build level would improve usability, eliminating the need for users to search for the child job link in the console output.

For example:

[llxia]

PRs:
#6521
#6523
#6524

[pshipton]

We could backport this to v1.0.9.