OtlpJsonLogging{Signal}Exporters should have option to use low allocation OTLP marshalers

[jack-berg]

We recently introduced optional low allocation OTLP marshalers to the OtlpGrpc{Signal}Exporter and OtlpHttp{Signal}Exporter classes:

• Low allocation OTLP logs marshaler (#6429)
• Low allocation OTLP metrics marshaler (#6422)
• Low allocation OTLP trace marshaler (#6410)
• Add memory mode support to OTLP exporters (#6430)
• Marshal span status description without allocation (#6423)
• Add private constructors for stateless marshalers (#6434)

We should add this same option to the OtlpJsonLogging{Signal}Exporters, since these use the same marshalers to write JSON logs.