bug: Fluent Bit custom docker image issue

### Describe the issue

Even after specifying custom docker image for fluent bit, default image is being used in the fluent-bit pods.

Fluentbit daemonset configuration
```
apiVersion: fluentbit.fluent.io/v1alpha2
kind: FluentBit
metadata:
name: fluent-bit
namespace: fluent
labels:
app.kubernetes.io/name: fluent-bit
spec:
{{- with .Values.fluentbit.annotations }}
annotations:
{{- toYaml . | nindent 4 }}
{{- end }}
image: eu.gcr.io/fluent-operator-fluentbit:3.1.7-sap0
{{- with .Values.fluentbit.imagePullSecrets }}
imagePullSecrets:
{{- toYaml . | nindent 4 }}
{{- end }}
imagePullPolicy: {{ .Values.fluentbit.imagePullPolicy }}
positionDB:
hostPath:
path: /var/lib/fluent-bit/
resources:
requests:
cpu: {{ .Values.fluentbit.requests.cpu }}
memory: {{ .Values.fluentbit.requests.memory }}
limits:
cpu: {{ .Values.fluentbit.limits.cpu }}
memory: {{ .Values.fluentbit.limits.memory }}
fluentBitConfigName: fluent-bit-only-config
tolerations:
- operator: Exists
```

#### Actual fluentbit daemonset pod

### To Reproduce

1. Use custom docker image for FluentBit
2. Create a fluent-bit daemon set

### Expected behavior

Fluent bit pods should be created with the custom docker image.

### Your Environment

```markdown
- Fluent Operator version: 3.1.0
- Container Runtime: docker
- Operating system: linux
- Kernel version: 6.6.35-cloud-amd64
```

### How did you install fluent operator?
Using helm chart version 3.1.0

### Additional context

_No response_