Add attribute validation to attributeAssign

[kswiatek92]

closes #5140

Impact

• New migrations
• New/Updated API fields or mutations
• Deprecated API fields or mutations
• Removed API types, fields, or mutations

Pull Request Checklist

• Privileged queries and mutations are guarded by proper permission checks
• Database queries are optimized and the number of queries is constant
• Database migration files are up to date
• The changes are tested
• GraphQL schema and type definitions are up to date
• Changes are mentioned in the changelog

[codecov]

Codecov Report

Merging #5423 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #5423   +/-   ##
=======================================
  Coverage   91.14%   91.14%           
=======================================
  Files         283      283           
  Lines       18341    18358   +17     
  Branches     1613     1617    +4     
=======================================
+ Hits        16716    16733   +17     
  Misses       1196     1196           
  Partials      429      429           

Impacted Files	Coverage Δ
saleor/graphql/product/resolvers.py	83.33% <ø> (ø)
saleor/graphql/core/types/common.py	100.00% <100.00%> (ø)
saleor/graphql/product/mutations/attributes.py	98.11% <100.00%> (+0.05%)	⬆️
saleor/graphql/account/mutations/base.py	98.77% <0.00%> (+0.01%)	⬆️
saleor/graphql/account/mutations/account.py	98.48% <0.00%> (+0.01%)	⬆️

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[maarcingebala]

@IKarbowiak Can you please re-review this one?