Fix vocabulary search using "0" as the search string

[miguelvaara]

Reasons for creating this PR

Fix the remaining cases in #1260 ; the REST API search using "0" has been fixed in #1261 and #1276, but searches for "0" in the web UI are still not working until this PR.

Link to relevant issue(s), if any

• Closes Vocabulary search using "0" as the query argument throws an error #1260

Description of the changes in this PR

• fix ConceptSearchParameters.getSearchTerm() so it looks at the right URL parameter q even when its value is "0"
• rename the test provider method testSearchWithZeroData into provideSearchWithZeroData to avoid PHPUnit considering it a test case and complaining that it's "Risky" because it doesn't perform any assertions

Known problems or uncertainties in this PR

n/a

Checklist

• phpUnit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works (if not, explain why below)
• The PR doesn't introduce unintended code changes (e.g. empty lines or useless reindentation)

[codecov]

Codecov Report

Merging #1267 (e5b066d) into master (3a1902b) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##             master    #1267   +/-   ##
=========================================
  Coverage     69.36%   69.36%           
  Complexity     1650     1650           
=========================================
  Files            32       32           
  Lines          4047     4047           
=========================================
  Hits           2807     2807           
  Misses         1240     1240           

Impacted Files	Coverage Δ
model/sparql/GenericSparql.php	92.24% <ø> (ø)
model/ConceptSearchParameters.php	85.55% <100.00%> (ø)

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[osma]

Can you please update the PR title and description so it corresponds to current status?

[kinow]

Hadn't seen this PR, I think it's also related to the zeroes in the beginning of the search, sorry! Feel free to close mine and centralize on this one if you prefer, or use anything from that PR too 👍

[osma]

Need to fix the conflicts caused by #1276.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[osma]

I fixed the conflicts, cleaned up the PR (removed useless test data), edited the PR title, rewrote the PR description, and tested this. I think it should be good to go now. Will wait for QA jobs, do a final check, then merge if there are no problems.