LongTaskTimer created from a Timed annotation doesn't enable histogram

[shakuzen]

Describe the bug
With frameworks, e.g. Spring Boot, that support the Micrometer @Timed annotation, you can make LongTaskTimers by setting the attribute longTask = true. There is also a histogram attribute which currently has no effect with longTask = true.

Environment

• Micrometer version: 1.5.0 - 1.7.2
• Micrometer registry: e.g. prometheus
• OS: macOS
• Java version: openjdk version "16.0.1" 2021-04-20

To Reproduce
How to reproduce the bug:
In a Spring Boot web app, make a controller like the following:

@Timed(longTask = true, value = "some.job", histogram = true)
@GetMapping("long")
void longTask() throws InterruptedException {
    Thread.sleep(new Random().nextInt(180_000));
}

Expected behavior
The created LongTaskTimer some.job should have histograms enabled, but it does not.

Additional context
LongTaskTimers were enhanced in the 1.5 release to add histogram support. It seems we missed updating the code where a LongTaskTimer was built from an instance of the @Timed annotation.