to_json does not properly escape values with single quotes

[C-Loftus]

Description

If a json key has a single quote, when it is serialized by pygeoapi's to_json custom jinja filter, it is not escaped correctly and thus causes a syntax error if it is passed into other functions expecting json.

I came across this when rendering covjson data with displayCovJSON(JSON.parse('{{ data | to_json | safe }}'), { display: true })

Steps to Reproduce

• query an endpoint which returns covjson
• make sure there is a key containing a single quote
  • i.e. say that the following key is part of the covjson output. Note the word its' in the description below

 "17":{
            "type":"Parameter",
            "description":{
                "en":"Average daily lake/reservoir spillway release in cubic feet per second (cfs). Lake/reservoir spillway release refers to water released from a reservoir via its' spillway structure(s) (typically open channels)."
            },
            "unit":{
                "symbol":"cfs"
            },
            "observedProperty":{
                "id":"17",
                "label":{
                    "en":"Lake/Reservoir Release - Spillway"
                }
            }
        },

• try to render the covjson leaflet map
• it should fail to render the map

Expected behavior

If I used the built in json filter: tojson instead of the custom one to_json, it works and escapes the character correctly. I expected to_json to have this same behavior, but also encode time as it is intended to.

Environment

• OS: MacOS Sonoma 14.3
• Python version: 3.10
• pygeoapi version: 0.19.dev0

Additional context

I ensured the returned covjson is valid and if I query with f=json and paste it into the covjson playground, it is valid

Image below shows the invalid json string inside of displayCovJSON(JSON.parse('{{ data | to_json | safe }}'), { display: true })