This PR was merged into the 4.3 branch.

Discussion
----------

[TwigBridge] Add row_attr to all form themes

| Q             | A
| ------------- | ---
| Branch?       | 4.3
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #33552
| License       | MIT
| Doc PR        | -

The rules I applied:
- Always done on the first HTML tag of the row.
- Current existing row attrs (`class` or `style`) are applied unless they are defined by the `row_attr` override. They can be removed if they are explicitly set to `false`.

Starting from:
```
<div class="form-group">
```

With `row_attr: {foo: "bar"}`:
```
<div foo="bar" class="form-group">
```

With `row_attr: {class: "ccc"}`:
```
<div class="ccc">
```

With `row_attr: {foo: "bar", class: false}`:
```
<div foo="bar">
```

Commits
-------

dfdcbb4 [TwigBridge] Add row_attr to all form themes