TypeError in CreateForEachBundle when processing config with integer or boolean schema types

Problem/Motivation

When using recipe config actions that utilize `CreateForEachBundle` (such as `createForEachIfNotExists`, `createForEach`, or any action using wildcard config names like `node.type.*`), a TypeError occurs if the configuration being processed contains fields defined as `integer` or `boolean` types in the config schema.

Error:
TypeError: str_replace(): Argument #3 ($subject) must be of type array|string, int given
in CreateForEachBundle.php on line 128

Steps to reproduce

1. Create a Drupal recipe with a `createForEachIfNotExists` action targeting a wildcard pattern (e.g., `node.type.*`)
2. Include configuration that references entities with integer or boolean schema types (e.g., `ai_automator` config with `weight: 100` and `edit_mode: false`)
3. Apply the recipe using `php web/core/scripts/drupal recipe recipes/your_recipe`
4. Observe TypeError

Example recipe

Root Cause:

1. Config Schema Typing: When configuration is loaded and validated against config schemas (e.g., `ai_automators.schema.yml`), fields typed as `integer` or `boolean` are converted from YAML to native PHP integers and booleans. This is correct and expected behavior.

2. Array Key Processing: During the schema validation process, if configuration data structures contain numeric keys, these keys may be represented as PHP integers (depending on how YAML is parsed and validated).

3. Missing Type Check: The `CreateForEachBundle::replacePlaceholders()` method attempts to perform `str_replace()` on ALL array keys without first checking if the key is a string. When it encounters an integer key, `str_replace()` throws a TypeError because it only accepts string or array types for its third argument.

Proposed resolution

Thanks to guidance from @phenaproxima,

Wrap the str_replace() call in an is_string() check. Only perform placeholder replacement on string keys and values, since non-string types (integers, booleans, floats, null) cannot contain placeholders anyway.

Remaining tasks

MR to follow

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet