Add tab for Digital Collections

[jazairi]

Why these changes are being introduced:

Digital Collections stakeholders would like an
easier way to view TIMDEX search results for that
platform.

Relevant ticket(s):

• USE-570

How this addresses that need:

This adds a Digital Collections tab that is
gated by the Feature class.

Side effects of this change:

None.

Developer

Accessibility

• ANDI or WAVE has been run in accordance to our guide.
• This PR contains no changes to the view layer.
• New issues flagged by ANDI or WAVE have been resolved.
• New issues flagged by ANDI or WAVE have been ticketed (link in the Pull Request details above).
• No new accessibility issues have been flagged.

New ENV

• All new ENV is documented in README.
• All new ENV has been added to Heroku Pipeline, Staging and Prod.
• ENV has not changed.

Approval beyond code review

• UXWS/stakeholder approval has been confirmed.
• UXWS/stakeholder review will be completed retroactively.
• UXWS/stakeholder review is not needed.

Additional context needed to review

The PR build is connected to TIMDEX dev, so Digital Collections results should be visible.

Code Reviewer

Code

• I have confirmed that the code works as intended.
• Any CodeClimate issues have been fixed or confirmed as
  added technical debt.

Documentation

• The commit message is clear and follows our guidelines
  (not just this pull request message).
• The documentation has been updated or is unnecessary.
• New dependencies are appropriate or there were no changes.

Testing

• There are appropriate tests covering any new functionality.
• No additional test coverage is required.

[coveralls]

Coverage Report for CI Build 30661671501

Warning

Build has drifted: This PR's base is out of sync with its target branch, so coverage data may include unrelated changes.
Quick fix: rebase this PR. Learn more →

Coverage increased (+0.001%) to 98.385%

Details

• Coverage increased (+0.001%) from the base build.
• Patch coverage: 3 of 3 lines across 3 files are fully covered (100%).
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	1548
Covered Lines:	1523
Line Coverage:	98.39%
Coverage Strength:	85.66 hits per line

---

💛 - Coveralls

[qltysh]

❌ 4 blocking issues (4 total)

Tool	Category	Rule	Count
rubocop	Lint	Assignment Branch Condition size for query\_timdex is too high. [<10, 21, 17> 28.81/17]	1	❌
rubocop	Lint	Cyclomatic complexity for query\_timdex is too high. [10/7]	1	❌
rubocop	Lint	Method has too many lines. [20/10]	1	❌
rubocop	Lint	Perceived complexity for query\_timdex is too high. [11/8]	1	❌

[JPrevost]

I think the 2 qlty flagged "line is too long" comments are worth cleaning up but I won't block on it.

[jazairi]

@JPrevost Thanks for flagging that. FYI, I fixed and merged those without re-review.