refactor(eslint-plugin): [no-shadow] use findVariable from utils

[rafaelss95]

Context: #3871 (comment)

[typescript-eslint]

Thanks for the PR, @rafaelss95!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[codecov]

Codecov Report

Merging #3921 (46f1c89) into master (dda9cee) will decrease coverage by 0.01%.
The diff coverage is 94.11%.

@@            Coverage Diff             @@
##           master    #3921      +/-   ##
==========================================
- Coverage   93.51%   93.49%   -0.02%     
==========================================
  Files         151      151              
  Lines        8144     8137       -7     
  Branches     2584     2582       -2     
==========================================
- Hits         7616     7608       -8     
  Misses        167      167              
- Partials      361      362       +1     

Flag	Coverage Δ
unittest	93.49% <94.11%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ges/eslint-plugin/src/rules/no-inferrable-types.ts	93.33% <ø> (ø)
...nt-plugin/src/rules/no-unused-vars-experimental.ts	91.39% <ø> (ø)
packages/eslint-plugin/src/rules/no-shadow.ts	75.40% <75.00%> (-1.76%)	⬇️
...plugin/src/rules/explicit-module-boundary-types.ts	89.47% <100.00%> (ø)
packages/eslint-plugin/src/rules/no-type-alias.ts	100.00% <100.00%> (ø)
...es/eslint-plugin/src/rules/no-use-before-define.ts	91.20% <100.00%> (+0.09%)	⬆️
.../eslint-plugin/src/util/explicitReturnTypeUtils.ts	100.00% <100.00%> (ø)

[nx-cloud]

Nx Cloud Report

CI ran the following commands for commit 46f1c89. Click to see the status, the terminal output, and the build insights.

📂 See all runs for this branch

Status	Command
	nx test @typescript-eslint/eslint-plugin-internal
	nx test @typescript-eslint/eslint-plugin-tslint
	nx test @typescript-eslint/eslint-plugin
	nx test @typescript-eslint/eslint-plugin-tslint
	nx test @typescript-eslint/eslint-plugin
	nx test @typescript-eslint/eslint-plugin-tslint
	nx test @typescript-eslint/eslint-plugin
	nx run-many --target=typecheck --all --parallel
	nx test @typescript-eslint/parser
	nx test @typescript-eslint/experimental-utils
	nx test @typescript-eslint/scope-manager
	nx run-many --target=build --all --parallel
	nx run-many --target=build --all --parallel
	nx test @typescript-eslint/visitor-keys
	nx test @typescript-eslint/parser
	nx test @typescript-eslint/experimental-utils
	nx test @typescript-eslint/typescript-estree
	nx test @typescript-eslint/scope-manager
	nx run-many --target=build --all --parallel
	nx test @typescript-eslint/visitor-keys

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[nx-cloud]

Nx Cloud Report

CI ran the following commands for commit 46f1c89. Click to see the status, the terminal output, and the build insights.

📂 See all runs for this branch

Status	Command
	nx test @typescript-eslint/eslint-plugin-internal
	nx test @typescript-eslint/eslint-plugin-tslint
	nx test @typescript-eslint/eslint-plugin
	nx test @typescript-eslint/eslint-plugin-tslint
	nx test @typescript-eslint/eslint-plugin
	nx test @typescript-eslint/eslint-plugin-tslint
	nx test @typescript-eslint/eslint-plugin
	nx run-many --target=typecheck --all --parallel
	nx test @typescript-eslint/parser
	nx test @typescript-eslint/experimental-utils
	nx test @typescript-eslint/scope-manager
	nx run-many --target=build --all --parallel
	nx run-many --target=build --all --parallel
	nx test @typescript-eslint/visitor-keys
	nx test @typescript-eslint/parser
	nx test @typescript-eslint/experimental-utils
	nx test @typescript-eslint/typescript-estree
	nx test @typescript-eslint/scope-manager
	nx run-many --target=build --all --parallel
	nx test @typescript-eslint/visitor-keys

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[bradzacher]

sweet - thanks for cleaning this up!