fix(cdk/text-field): Long multiline textfield focus issue

[mistrykaran91]

When we have a long multiline textfield and put the cursor on almost an end (For example, on 3rd last line), the scroll moves up to the top of textarea. This fix will cache the scrollTop in theresizeToFitContent method

Fixes #20255

[mistrykaran91]

@mmalerba, #8992 seems to be a similar issue.

[mmalerba]

This looks good to me!

[mistrykaran91]

@mmalerba let me know if you want me to rebase the branch with the latest changes in main.

[mmalerba]

It looks like there's no conflicts so its fine for now, we just need to run it against google's internal tests and see if anything fails

[mistrykaran91]

@mmalerba just to be double sure won't it fix this one too - #8992 ? Or I'm missing something

[Sn0oze]

Today I updated the CDK version from v18.x to v19.2.8 during the Angular v18 to v19 migration of our mono repo and noticed a regression in our textarea component that uses the CdkTextareaAutosize.
After some bisecting, I conclude that this fix must be the cause as the regression appears from version 19.2.4 and onwards, which is the first release that includes this fix.

The regression happens when enough rows have been inserted at the bottom of the text area to reach the maxRows limit and cause the textarea to overflow.
While inserting new rows, the scroll container does not properly scroll to the inserted rows.
This bug can also be observed on the official Auto-resizing textarea example.
To reproduce the bug it is enough to focus the text area and keep the enter key pressed.
The same interaction works as expected in v18 of the Auto-resizing textarea example