fix: pass strings to JSON.stringify in --json mode

[lukekarrys]

In refactoring this behavior previously plain strings were no longer being passed through JSON.stringify even in json mode. This commit changes that to the previous behavior which fixes the bug in npm view. This also required changing the behavior of npm pkg which relied on this.

Fixes #7537

[npm-cli-bot]

no statistically significant performance changes detected

timing results

|**app-large**|clean|lock-only|cache-only|modules-only|no-lock|no-cache|no-modules|no-clean|show-version|run-script|cache-only
peer-deps|no-clean
audit| |---|---|---|---|---|---|---|---|---|---|---|---|---| |npm@latest|31.815 ±0.29|10.675 ±0.02|11.826 ±0.04|1.578 ±0.01|1.569 ±0.00|1.292 ±0.01|8.426 ±0.01|1.296 ±0.00|0.140 ±0.00|0.168 ±0.00|15.101 ±0.16|2.134 ±0.05| |#7540|33.871 ±6.18|10.658 ±0.04|11.818 ±0.01|1.534 ±0.00|1.548 ±0.00|1.274 ±0.00|8.301 ±0.02|1.280 ±0.04|0.138 ±0.00|0.165 ±0.00|14.673 ±0.21|2.100 ±0.03| |**app-medium**|clean|lock-only|cache-only|modules-only|no-lock|no-cache|no-modules|no-clean|show-version|run-script|cache-only
peer-deps|no-clean
audit| |---|---|---|---|---|---|---|---|---|---|---|---|---| |npm@latest|25.024 ±0.40|8.029 ±0.00|8.932 ±0.02|1.483 ±0.01|1.500 ±0.02|1.432 ±0.02|5.838 ±0.04|1.314 ±0.01|0.138 ±0.00|0.166 ±0.00|9.985 ±0.06|2.013 ±0.09| |#7540|24.886 ±0.76|7.996 ±0.00|8.873 ±0.03|1.500 ±0.02|1.492 ±0.01|1.405 ±0.01|5.826 ±0.01|1.311 ±0.01|0.138 ±0.00|0.165 ±0.00|9.898 ±0.13|1.947 ±0.02|