fix(fabric.Image): fix wrong scaling value for the y axis in renderFill

[asturur]

Probably a copy-paste error, we were using scaleX in place of scaleY in a place.

close #6729

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[asturur]

Needs a small test.

[github-actions]

Code Coverage Summary

> fabric@4.3.1 coverage:report /home/runner/work/fabric.js/fabric.js
> nyc report --reporter=lcov --reporter=text

-----------|---------|----------|---------|---------|-----------------------------------------------
File       | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s                             
-----------|---------|----------|---------|---------|-----------------------------------------------
All files  |    82.7 |     76.9 |    85.6 |   82.46 |                                               
 fabric.js |    82.7 |     76.9 |    85.6 |   82.46 | ...,29558,29683,29763-29828,29951,30050,30267 
-----------|---------|----------|---------|---------|-----------------------------------------------

[github-actions]

Code Coverage Summary

> fabric@4.3.1 coverage:report /home/runner/work/fabric.js/fabric.js
> nyc report --reporter=lcov --reporter=text

-----------|---------|----------|---------|---------|-----------------------------------------------
File       | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s                             
-----------|---------|----------|---------|---------|-----------------------------------------------
All files  |    82.7 |    76.91 |    85.6 |   82.46 |                                               
 fabric.js |    82.7 |    76.91 |    85.6 |   82.46 | ...,29558,29683,29763-29828,29951,30050,30267 
-----------|---------|----------|---------|---------|-----------------------------------------------