chore: remove listx dependency

[kevgo]

listx doesn't seem to be used anywhere in this repo. Looking at https://github.com/ory/x/blob/master/tools/listx/main.go, it seem replacable with find -f -name "*.go" -not -path "./vendor/". Given that there isn't a vendor folder anymore, this seems obsolete altogether.

Checklist

• I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change
  introduces a new feature.
• I am following the
  contributing code guidelines.
• I have read the security policy.
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security vulnerability, I
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• I have added tests that prove my fix is effective or that my feature
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• I have added or changed the documentation.

[codecov]

Codecov Report

Merging #1021 (7d47e4b) into master (f68646e) will decrease coverage by 0.01%.
The diff coverage is n/a.

❗ Current head 7d47e4b differs from pull request most recent head 7597eeb. Consider uploading reports for the commit 7597eeb to get more accurate results

@@            Coverage Diff             @@
##           master    #1021      +/-   ##
==========================================
- Coverage   78.06%   78.05%   -0.02%     
==========================================
  Files          83       83              
  Lines        3999     3992       -7     
==========================================
- Hits         3122     3116       -6     
+ Misses        598      597       -1     
  Partials      279      279              

Impacted Files	Coverage Δ
internal/driver.go	50.00% <0.00%> (-27.78%)	⬇️

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