fix: revert "fix: res.send of cy.intercept doesn't override json-related content types. "

[flotwig]

Reverts #17199

This PR was causing failures in cypress-example-recipes: https://app.circleci.com/pipelines/github/cypress-io/cypress/22275/workflows/eb6fc6d5-607e-4bf1-8cc6-c17ae12b0e03/jobs/817100

Reverting so we can get 8.0-release out.

[cypress-bot]

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[cypress]

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Test summary

18159 • 0 • 214 • 7 • 2

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Run details

Project	cypress
Status	Passed
Commit	059f657
Started	Jul 19, 2021 11:14 PM
Ended	Jul 19, 2021 11:25 PM
Duration	10:57 💡
OS	Linux Debian - 10.8
Browser	Multiple

View run in Cypress Dashboard ➡️

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Flakiness

	commands/net_stubbing_spec.ts		1
1	network stubbing > intercepting request > can intercept utf-8 request bodies without crashing
	retries.ui.spec.js		1
1	runner/cypress retries.ui.spec > opens attempt on each attempt failure for the screenshot, and closes after test passes

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