Bracket in regex causes code block comprehension to fail in text entry of pipeline central management

[nerophon]

Kibana version: 6.7.1 & 7.4.0

Describe the bug: When entering text into the Pipeline Central Management page pipeline definition text box, entering an escaped { character within a regex causes code block comprehension to fail. The bracket within the regex should be ignored in respect of code block comprehension, but instead it is treated as if it were a normal syntax element.

Example:

if [logBody] =~ "\[\{Correlation-ID.*" {
...

Steps to reproduce:

1. Create a pipeline via Central Pipeline Management
2. Attempt to put an escaped bracket within a regex match statement
3. Observe that code block comprehension fails, suggesting a syntax error where there is none

Expected behavior:
Brackets within a regex should be ignored in the context of code block comprehension.