breaking(middleware/devtools): remove checking old string option

[dai-shi]

This is something we forgot in #892.
Also did some refactor to remove our own options in DevtoolsOptions.

[dai-shi]

review request @devanshj

[github-actions]

Size Change: +725 B (+2%)

Total Size: 29.8 kB

Filename	Size	Change
dist/esm/middleware.js	3.09 kB	+137 B (+5%)	🔍
dist/middleware.js	3.22 kB	+149 B (+5%)	🔍
dist/system/middleware.development.js	3.18 kB	+137 B (+5%)	🔍
dist/system/middleware.production.js	2.04 kB	+71 B (+4%)
dist/umd/middleware.development.js	3.33 kB	+150 B (+5%)	🔍
dist/umd/middleware.production.js	2.05 kB	+81 B (+4%)

ℹ️ View Unchanged

Filename	Size
dist/context.js	518 B
dist/esm/context.js	448 B
dist/esm/index.js	400 B
dist/esm/middleware/immer.js	210 B
dist/esm/shallow.js	272 B
dist/esm/vanilla.js	377 B
dist/index.js	642 B
dist/middleware/immer.js	373 B
dist/shallow.js	318 B
dist/system/context.development.js	572 B
dist/system/context.production.js	393 B
dist/system/index.development.js	575 B
dist/system/index.production.js	385 B
dist/system/middleware/immer.development.js	292 B
dist/system/middleware/immer.production.js	187 B
dist/system/shallow.development.js	338 B
dist/system/shallow.production.js	253 B
dist/system/vanilla.development.js	444 B
dist/system/vanilla.production.js	270 B
dist/umd/context.development.js	662 B
dist/umd/context.production.js	488 B
dist/umd/index.development.js	787 B
dist/umd/index.production.js	564 B
dist/umd/middleware/immer.development.js	514 B
dist/umd/middleware/immer.production.js	371 B
dist/umd/shallow.development.js	447 B
dist/umd/shallow.production.js	344 B
dist/umd/vanilla.development.js	590 B
dist/umd/vanilla.production.js	378 B
dist/vanilla.js	456 B

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[devanshj]

This is something we forgot in #892.

Ah right. LGTM.