Revert "[data views] Move fields_for_wildcard to internal route"

[mattkime]

Reverts #159637

Isn't properly handling field conflicts

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 38ab538

Metrics [docs]

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
dataViews	44.6KB	44.6KB	-41.0B

Unknown metric groups

ESLint disabled line counts

id	before	after	diff
enterpriseSearch	13	15	+2
securitySolution	410	414	+4
total			+6

Total ESLint disabled count

id	before	after	diff
enterpriseSearch	14	16	+2
securitySolution	493	497	+4
total			+6

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@elasticmachine merge upstream