[aws-for-fluent-bit] firehose.extraOutputs doesn't use in template

**Describe the bug**
Even if user set `firehose.extraOutputs` helm template not referencing this key, but it refer `kinesis.extraOutputs`.

This led by following typo, `.Values.kinesis.extraOutputs` should be `.Values.firehose.extraOutputs`.

https://github.com/aws/eks-charts/blob/ef3f3145682b25cfb264a567d579ea59adcc561f/stable/aws-for-fluent-bit/templates/configmap.yaml#L186-L188

**Steps to reproduce**

Set firehose.extraOutputs in Values.yaml, but values are not referencing in `[OUTPUT]`.

```yaml
firehose:
enabled: true
match: "foo.*"
region: "us-east-1"
deliveryStream: "some-delivery-name"
dataKeys:
roleArn:
endpoint:
timeKey:
extraOutputs: |
replace_dots _
```

```yaml
[OUTPUT]
Name firehose
Match foo.*
region us-east-1
delivery_stream some-delivery-name
```

**Expected outcome**
```
[OUTPUT]
Name firehose
Match foo.*
region us-east-1
delivery_stream some-delivery-name
replace_dots _
```

**Environment**

* Chart name: aws-for-fluent-bit
* Chart version: 0.1.34
* Kubernetes version: n/a
* Using EKS (yes/no), if so version? n/a

**Additional Context**:

Start at stable/aws-for-fluent-bit/templates/configmap.yaml around lines 186-188 and compare the firehose and kinesis value references. Render the chart with the provided firehose.extraOutputs values, then confirm the generated [OUTPUT] block includes replace_dots under the firehose configuration.

Written by the indexing model from the issue text.