Fix #10988: Validate manifest has group_map during group_lookup init

[aranke]

Resolves #10988

Problem

dbt build --no-write-json was failing if there was no group map.

Solution

Validate manifest.group_map exists and add a test for the same.

Checklist

• I have read the contributing guide and understand what's expected of me.
• I have run this code in development, and it appears to resolve the stated issue.
• This PR includes tests, or tests are not required or relevant for this PR.
• This PR has no interface changes (e.g., macros, CLI, logs, JSON artifacts, config files, adapter interface, etc.) or this PR has already received feedback and approval from Product or DX.
• This PR includes type annotations for new and modified functions.

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 89.06%. Comparing base (6e1f64f) to head (9920ce4).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10995      +/-   ##
==========================================
- Coverage   89.12%   89.06%   -0.06%     
==========================================
  Files         183      183              
  Lines       23626    23630       +4     
==========================================
- Hits        21057    21047      -10     
- Misses       2569     2583      +14     

Flag	Coverage Δ
integration	86.36% <75.00%> (-0.13%)	⬇️
unit	62.78% <0.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
Unit Tests	62.78% <0.00%> (-0.02%)	⬇️
Integration Tests	86.36% <75.00%> (-0.13%)	⬇️

[gshank]

You're not actually checking that "group_map" exists, you're checking that "groups" exists. And "group_map" isn't actually an attribute of the Manifest, only the WritableManifest (it probably ought to be, along with parent_map and child_map, but let's do a followup for that). So you should check that "group_map" exists and if it doesn't, built it with "build_group_map".

[aranke]

You're not actually checking that "group_map" exists, you're checking that "groups" exists. And "group_map" isn't actually an attribute of the Manifest, only the WritableManifest (it probably ought to be, along with parent_map and child_map, but let's do a followup for that). So you should check that "group_map" exists and if it doesn't, built it with "build_group_map".

I'm not sure I follow here, will set up some time to chat about this sync today.