[BugFix] Fix star count return null rather zero bug for mv rewrite (backport #49288)

[mergify]

Why I'm doing:

• count(*) returns null instead of zero after mv rewrite
  

What I'm doing:

   // No needs to set `newProjections` since it will use aggColRefToAggMap to construct new projections,
      // otherwise it will cause duplicate projections(or wrong projections).
      // eg:
      // query: oldCol1 -> count()
      // newAggregations: newCol1 -> sum(oldCol1)
      // aggColRefToAggMap:  oldCol1 -> coalesce(newCol1, 0)
      // It will generate new projections as below:
      // newProjections: oldCol1 -> coalesce(newCol1, 0)

after:

 OUTPUT EXPRS:59: count
  PARTITION: RANDOM
  RESULT SINK
  3:Project
  |  <slot 59> : coalesce(80: count, 0)
  |  
  2:AGGREGATE (update finalize)
  |  output: sum(69: mock_062)
  |  group by: 
  |  
  1:Project
  |  <slot 69> : 69: mock_062
  |  
  0:OlapScanNode
     TABLE: tbl_mock_067
     PREAGGREGATION: ON
     partitions=1/120
     rollup: tbl_mock_067
     tabletRatio=1/1
     tabletList=12242
     cardinality=1
     avgRowSize=0.0
     MaterializedView: true

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• Doc
• Tool

Does this PR entail a change in behavior?

• Yes, this PR will result in a change in behavior.
• No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• Interface/UI changes: syntax, type conversion, expression evaluation, display information
• Parameter changes: default values, similar parameters but with different default values
• Policy changes: use new policy to replace old one, functionality automatically enabled
• Feature removed
• Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• I have added test cases for my bug fix or my new feature
• This pr needs user documentation (for new or modified features or behaviors)
  • I have added documentation for my new feature or new function
• This is a backport pr

Bugfix cherry-pick branch check:

• I have checked the version labels which the pr will be auto-backported to the target branch
  • 3.3
  • 3.2
  • 3.1
  • 3.0
  • 2.5

---

This is an automatic backport of pull request #49288 done by [Mergify](https://mergify.com). ## Why I'm doing: - count(*) returns null instead of zero after mv rewrite 

What I'm doing:

   // No needs to set `newProjections` since it will use aggColRefToAggMap to construct new projections,
      // otherwise it will cause duplicate projections(or wrong projections).
      // eg:
      // query: oldCol1 -> count()
      // newAggregations: newCol1 -> sum(oldCol1)
      // aggColRefToAggMap:  oldCol1 -> coalesce(newCol1, 0)
      // It will generate new projections as below:
      // newProjections: oldCol1 -> coalesce(newCol1, 0)

after:

 OUTPUT EXPRS:59: count
  PARTITION: RANDOM
  RESULT SINK
  3:Project
  |  <slot 59> : coalesce(80: count, 0)
  |  
  2:AGGREGATE (update finalize)
  |  output: sum(69: mock_062)
  |  group by: 
  |  
  1:Project
  |  <slot 69> : 69: mock_062
  |  
  0:OlapScanNode
     TABLE: tbl_mock_067
     PREAGGREGATION: ON
     partitions=1/120
     rollup: tbl_mock_067
     tabletRatio=1/1
     tabletList=12242
     cardinality=1
     avgRowSize=0.0
     MaterializedView: true

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• Doc
• Tool

Does this PR entail a change in behavior?

• Yes, this PR will result in a change in behavior.
• No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• Interface/UI changes: syntax, type conversion, expression evaluation, display information
• Parameter changes: default values, similar parameters but with different default values
• Policy changes: use new policy to replace old one, functionality automatically enabled
• Feature removed
• Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• I have added test cases for my bug fix or my new feature
• This pr needs user documentation (for new or modified features or behaviors)
  • I have added documentation for my new feature or new function
• This is a backport pr

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud