Specify result type of ConstraintSchemaInterface::getTableIndexes() method to IndexConstraint[]

[vjik]

Q	A
Is bugfix?	❌
New feature?	❌
Breaks BC?	❌
Fixed issues	-

[what-the-diff]

PR Summary

• Enhancement to the ConstraintSchemaInterface::getTableIndexes() method
  This PR adds an enhancement that updates the result type of the getTableIndexes() method in ConstraintSchemaInterface from a more general “array” type to the specific IndexConstraint[]. This modification enhances the precision of the data type, ensuring that the function only returns IndexConstraint elements.

• Removal of unused code in AbstractSchema::getTableIndexes()
  We have removed certain pieces of code from the getTableIndexes() method in AbstractSchema, enhancing code cleanliness and making the function more efficient by eliminating code that was not being used.

• Removal of an unnecessary import in AbstractDMLQueryBuilder
  This PR also includes a cleanup change that removes an unnecessary import of Yiisoft\Db\Constraint\IndexConstraint in the AbstractDMLQueryBuilder. This helps to reduce clutter and maintain neatness in our codebase.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (8a3d81f) 99.64% compared to head (b3be66b) 99.64%.

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #784      +/-   ##
============================================
- Coverage     99.64%   99.64%   -0.01%     
+ Complexity     1272     1271       -1     
============================================
  Files            63       63              
  Lines          3061     3060       -1     
============================================
- Hits           3050     3049       -1     
  Misses           11       11              

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