Fix alter column error in Postgres QueryBuilder (issue yiisoft#19929).

[daniil-khaletsky]

Q	A
Is bugfix?	✔️
New feature?	❌
Breaks BC?	❌
Fixed issues	#19929

[what-the-diff]

PR Summary

• Improvement of Query Builder
  The component responsible for building queries to the database, located in the framework/db/pgsql directory, underwent some significant modifications.

• Column Default Value Extraction
  The way we extract the default value of a column has been refined to ensure it is more accurate, using the preg_match function.

• Removal of Column Default Value
  Adjustments have been made using the preg_replace function to improve how we remove a column's default value from the column type.

• Alter Statement Addition
  An additional alter statement has been included to set the column's default value with the improved extracted value.

These improvements will ensure both a better management of the database column default values and an overall more efficient and reliable queries flow.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (73902f0) 48.90% compared to head (bea3284) 48.90%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #19930   +/-   ##
=======================================
  Coverage   48.90%   48.90%           
=======================================
  Files         445      445           
  Lines       42806    42806           
=======================================
  Hits        20935    20935           
  Misses      21871    21871           

Files Changed	Coverage Δ
framework/db/pgsql/QueryBuilder.php	43.95% <100.00%> (ø)

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[samdark]

@terabytesoftw is that something we want to fix in yiisoft/db?

[terabytesoftw]

@terabytesoftw is that something we want to fix in yiisoft/db?

I'm going to check this case, but in Yii3, all the default values work correctly and have tests.

[terabytesoftw]

@daniil-khaletsky You can add a unit test to properly check the case, thanks.