Add ability to disable multi-line string concatenation with ruff format

### Summary

Please change ruff format's behaviour for concatenating multi-line strings.

For example:

```py
outputFile.write(
"\n"
f"\n"
f"{xmlEscape(source)}\n"
"\n"
"\n",
)
```

Should not concatenate to

```py
outputFile.write(
f"\n\n{xmlEscape(source)}\n\n\n",
)
```

I cannot find a way to disable this behaviour - or disabling string concatenation in general when using ruff format.
Any suggestions on how to use ruff format without multiline string concatenation would be helpful.

### Reasoning

Multi-line strings split over new lines is usually a very intended form of syntax.
Splitting strings over multiple lines at fixed positions helps with readability.
I think there is more value in disabling this feature for ruff format than having it enabled.

Start by tracing Ruff format's handling of adjacent multi-line Python string literals and how formatter options are defined and applied. Check the existing formatter tests, if present, for string concatenation behavior; done means a documented configuration can disable this concatenation while preserving the requested split strings.

Written by the indexing model from the issue text.