External-DNS sidecar returns wrong content type

[sholdee]

Describe the bug
gravity-external-dns:v0.28.7 is returning an invalid Content-Type value application/json; charset=UTF-8

To Reproduce
Deploy external-dns with sidecar v0.28.7.

Expected behavior
Returns application/external.dns.webhook+json;version=1

Logs

time="2025-11-03T02:43:42Z" level=info msg="GitCommitShort=unknown, GoVersion=go1.24.6, Platform=linux/arm64, UserAgent=ExternalDNS/v20250902-v0.19.0" 
time="2025-11-03T02:43:42Z" level=info msg="Using inCluster-config based on serviceaccount-token" 
time="2025-11-03T02:43:42Z" level=info msg="Created GatewayAPI client https://10.43.0.1:443" 
time="2025-11-03T02:43:42Z" level=info msg="Instantiating new Kubernetes client" 
time="2025-11-03T02:43:42Z" level=info msg="Using inCluster-config based on serviceaccount-token" 
time="2025-11-03T02:43:42Z" level=info msg="Created Kubernetes client https://10.43.0.1:443" 
time="2025-11-03T02:43:43Z" level=fatal msg="wrong content type returned from server: application/json; charset=UTF-8"

Version and Deployment (please complete the following information):

• Gravity version: v0.28.7
• External-DNS version: v0.19.0
• Deployment: Helm

Additional context
Sidecar tag 906a956337f4f318bc6dc0ad74e02a02f81a780f1 works.