fix: Unable to find JSON Schema ID: default

[splaunov]

When creating identity with admin api the following error is generated:

Unable to find JSON Schema ID: default

[github.com/ory/kratos/schema.Schemas.GetByID](http://github.com/ory/kratos/schema.Schemas.GetByID)
/go/src/github.com/ory/kratos/schema/schema.go:37 
[github.com/ory/kratos/identity.(*Validator](http://github.com/ory/kratos/identity.(*Validator)).ValidateWithRunner
/go/src/github.com/ory/kratos/identity/validator.go:40 
[github.com/ory/kratos/identity.(*Validator](http://github.com/ory/kratos/identity.(*Validator)).Validate 

This happens if there is no schema id default in the config.

Related issue(s)

Checklist

• [ x] I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change
  introduces a new feature.
• [ x] I am following the
  contributing code guidelines.
• [ x] I have read the security policy.
• [ x] 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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  the changes.
• 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.

Further Comments

[aeneasr]

@splaunov thank you for the many PRs you have created. Do you have time do address some of the feedback we provide? It is critical to get those in, in order to be able to merge things upstream. Thanks

[codecov]

Codecov Report

Merging #2393 (454e6b7) into master (aee2b1e) will decrease coverage by 1.46%.
The diff coverage is 74.40%.

❗ Current head 454e6b7 differs from pull request most recent head bab663e. Consider uploading reports for the commit bab663e to get more accurate results

@@            Coverage Diff             @@
##           master    #2393      +/-   ##
==========================================
- Coverage   76.56%   75.10%   -1.47%     
==========================================
  Files         318      292      -26     
  Lines       17298    15693    -1605     
==========================================
- Hits        13244    11786    -1458     
+ Misses       3121     2986     -135     
+ Partials      933      921      -12     

Impacted Files	Coverage Δ
cmd/courier/watch.go	72.41% <0.00%> (ø)
cmd/jsonnet/root.go	100.00% <ø> (ø)
cmd/remote/status.go	0.00% <0.00%> (ø)
cmd/remote/version.go	0.00% <0.00%> (ø)
continuity/test/persistence.go	100.00% <ø> (ø)
driver/registry.go	73.33% <ø> (ø)
hash/hasher_argon2.go	72.72% <0.00%> (ø)
identity/handler_import.go	63.04% <0.00%> (ø)
identity/identity_verification.go	68.96% <ø> (ø)
selfservice/flow/login/handler.go	80.83% <ø> (ø)
... and 189 more

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[aeneasr]

Thank you so much for following up :))