fix(storage-plugin): require only getItem and setItem on engines

[arturovt]

This commit updates the signature of the StorageEngine interface
and removes unnecessary properties that are not being used by the storage
plugin. The properties length, removeItem, and clear have been removed.
This change makes it easier to maintain storage engines that implement the
interface because only the necessary properties will be required. It is important
to note that this change is not considered a breaking change since properties are
being removed rather than added.

[nx-cloud]

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• nx run-many --target=test --all --configuration=ci --maxWorkers=4
• nx run-many --target=build --all

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[bundlemon]

BundleMon

Unchanged files (3)

Status	Path	Size	Limits
✅	fesm2015/ngxs-store.js	94.47KB	125KB / +0.5%
✅	fesm2015/ngxs-store-operators.js	6.23KB	15KB / +0.5%
✅	fesm2015/ngxs-store-internals.js	3.57KB	20KB / +0.5%

No change in files bundle size

Unchanged groups (3)

Status	Path	Size	Limits
✅	@ngxs/store(esm2015)[gzip] ./esm2015/**/*.js	180.26KB	+1%
✅	@ngxs/store(umd)[gzip] ./bundles/*.umd.js	36.55KB	+1%
✅	@ngxs/store(fesm2015)[gzip] ./fesm2015/*.js	25.02KB	+1%

Final result: ✅

View report in BundleMon website ➡️

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Current branch size history | Target branch size history

[bundlemon]

BundleMon (NGXS Plugins)

Files updated (2)

Status	Path	Size	Limits
✅	Plugins(umd)[gzip] storage-plugin/bundles/ngxs-storage-plugin.um d.js	7.97KB (+28B +0.34%)	+1%
✅	Plugins(fesm2015)[gzip] storage-plugin/fesm2015/ngxs-storage-plugin.j s	3.7KB (+28B +0.74%)	+1%

Unchanged files (12)

Status	Path	Size	Limits
✅	Plugins(umd)[gzip] router-plugin/bundles/ngxs-router-plugin.umd. js	7.41KB	+1%
✅	Plugins(umd)[gzip] websocket-plugin/bundles/ngxs-websocket-plugi n.umd.js	6.92KB	+1%
✅	Plugins(umd)[gzip] hmr-plugin/bundles/ngxs-hmr-plugin.umd.js	6.89KB	+1%
✅	Plugins(umd)[gzip] form-plugin/bundles/ngxs-form-plugin.umd.js	3.44KB	+1%
✅	Plugins(fesm2015)[gzip] router-plugin/fesm2015/ngxs-router-plugin.js	3.09KB	+1%
✅	Plugins(umd)[gzip] devtools-plugin/bundles/ngxs-devtools-plugin. umd.js	2.75KB	+1%
✅	Plugins(fesm2015)[gzip] form-plugin/fesm2015/ngxs-form-plugin.js	2.67KB	+1%
✅	Plugins(fesm2015)[gzip] hmr-plugin/fesm2015/ngxs-hmr-plugin.js	2.65KB	+1%
✅	Plugins(fesm2015)[gzip] websocket-plugin/fesm2015/ngxs-websocket-plug in.js	2.59KB	+1%
✅	Plugins(umd)[gzip] logger-plugin/bundles/ngxs-logger-plugin.umd. js	2.53KB	+1%
✅	Plugins(fesm2015)[gzip] devtools-plugin/fesm2015/ngxs-devtools-plugin .js	2.17KB	+1%
✅	Plugins(fesm2015)[gzip] logger-plugin/fesm2015/ngxs-logger-plugin.js	2.01KB	+1%

Total files change +56B +0.1%

Groups updated (3)

Status	Path	Size	Limits
✅	All Plugins(esm2015)[gzip] ./-plugin/esm2015/**/.js	109.49KB (+670B +0.6%)	+1%
✅	All Plugins(umd)[gzip] ./-plugin/bundles/.umd.js	37.92KB (+28B +0.07%)	+1%
✅	All Plugins(fesm2015)[gzip] ./-plugin/fesm2015/.js	18.88KB (+28B +0.15%)	+1%

Final result: ✅

View report in BundleMon website ➡️

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Current branch size history | Target branch size history

[bundlemon]

BundleMon (Integration Projects)

Files updated (3)

Status	Path	Size	Limits
✅	Main bundles(Gzip) hello-world-ng13-ivy/dist-integration/main.(h ash).js	69.83KB (-13B -0.02%)	+1%
✅	Main bundles(Gzip) hello-world-ng14-ivy/dist-integration/main.(h ash).js	64.82KB (-18B -0.03%)	+1%
✅	Main bundles(Gzip) hello-world-ng12-ivy/dist-integration/main.(h ash).js	67.97KB (-23B -0.03%)	+1%

Total files change -54B -0.03%

Final result: ✅

View report in BundleMon website ➡️

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Current branch size history | Target branch size history

[codeclimate]

Code Climate has analyzed commit 4e667b1 and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 100.0% (50% is the threshold).

This pull request will bring the total coverage in the repository to 96.7% (0.0% change).

View more on Code Climate.

[Carniatto]

LGTM