SF-3170 Show a summary message when no training books are selected

[josephmyers]

I opted for a minimalistic solution here, because this seems to be a rare use case, based on a conversation with Nathaniel. We need to support it, but most target languages won't be in the NLLB. We can certainly do more with the UI -- on the Summary and Training pages -- but apparently it's not necessary to guide them down this path too forcefully.

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This change is 

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.05%. Comparing base (4f60099) to head (93f0c3f).
Report is 78 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2971   +/-   ##
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  Coverage   82.05%   82.05%           
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  Files         544      544           
  Lines       31623    31623           
  Branches     5122     5139   +17     
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  Hits        25949    25949           
+ Misses       4917     4905   -12     
- Partials      757      769   +12     

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[Nateowami]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @josephmyers)

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src/SIL.XForge.Scripture/ClientApp/src/app/translate/draft-generation/draft-generation-steps/draft-generation-steps.component.html line 215 at r1 (raw file):

        <mat-card class="confirm-section mat-elevation-z2">
          @if (selectedTrainingBooksCollapsed().length === 0) {
            <span>No training books selected</span>

I18n

[josephmyers]

Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion (waiting on @Nateowami)

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src/SIL.XForge.Scripture/ClientApp/src/app/translate/draft-generation/draft-generation-steps/draft-generation-steps.component.html line 215 at r1 (raw file):

Previously, Nateowami wrote…

I18n

Oops, thanks

[Nateowami]

Reviewed 2 of 2 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @josephmyers)