Improve column option for fact box in news and locale news templates

[padms]

Ticking on/off single column layout gives single column (and also does so in prod today), and we prefer single column as default - both for local news and "regular" news. This is used the most in our news articles (this can potentially be moved to the list of fixes after launch).
Ref sign off comments on #3306

[padms]

@meols The factbox defaults (or forces to be single even if ticked off ) to single column when the content length is less than 800 characters. It will show two columns only if single column is off and content characters is above 800 characters.

If you check the page https://www.equinor.com/news/2022-12-30-electrical-systems-infrastructure-contract, there are two fact boxes, both have unset "isSingleColumn" which means they are two columns by default. The first factbox shows two columns because it has 1300 characters which is > 800 , but the second one has 600 characters so it shows as single column.

The confusion here is around the consideration of character count. How do you want the behavior?

Also, the image option seems like something that is newly introduced after upgrade. I have checked the occurrences in past news and found no usage. But looks like teaser but with two column ( more than 800 characters) it behaves like shown in this test page
https://web-global-development-equinor-web-sites-dev.c2.radix.equinor.com/news/factbox-duplicate

[padms]

For now,

• We are making single column true by default for all the factboxes created in future.
• Making the "isSingleColumn" option readonly until the character count reaches 800 limit, and only enable it so editors can turn it off to make it two column.
• Modify the description to explicitly explain this behavior.

[equinorpiyush]

Hi @meols
Here are the changes that I've done in this task

• Set Single column layout default to on (true) for new Factbox entries.
• Kept the existing readOnly rule: toggle stays disabled while content text length is below 800.
• Added guard logic to auto-reset toggle to true if content drops below 800 and it was off.
• Kept toggle editable only when content text length is 800 or more.
• Updated field description/type consistency to match the final behavior.

Could you please verify and let me know if anything else is required or needs to be changed.

Thank you!!