[backport] YAML editor barfs on sequences

[BoykoAlex]

Port into 4.x stream #1660

Error in editor:

Expecting a 'Object' but got a 'Sequence' node vscode-spring-boot(YAML_EXPECT_TYPE_FOUND_SEQUENCE)

Looks like it is emitted by this tooling? You get it when the YAML contains a sequence (a.k.a. array). Example:

spring:
  application:
    name: hello
  grpc:
    client:
      default-channel:
        negotiation-type: plaintext
        address: localhost:9092
        service-config:
          methodConfig:
            - name:
                - service: "com.dm4nk.gradlesandbox.user.proto.v1.UserService"
                  method: "User"
              retryPolicy:
                maxAttempts: "5"
                initialBackoff: "0.5s"
                maxBackoff: "1s"
                backoffMultiplier: "2"
                retryableStatusCodes: "UNAVAILABLE,UNKNOWN"

The YAML is legal. The target bean that it binds to doesn't know about the sequences (it's just Map<String,Object>), so maybe the error comes from that side?

[BoykoAlex]

Fixed via 0001b2c