Remove functions deprecated in testthat edition 3

[chrisholbrook]

After upgrading to testthat edition 3, some tests are throwing warnings about deprecated functions. All calls to deprecated functions should be removed, perhaps following this guidance: https://www.tidyverse.org/blog/2022/02/upkeep-testthat-3/

E.g.,

Warning (test-read_glatos_receivers.r:1:1): (code run outside of test_that())
context() was deprecated in the 3rd edition.
Backtrace:
▆

1. └─testthat::context("Check read_glatos_receivers") at test-read_glatos_receivers.r:1:1
2. └─testthat:::edition_deprecate(3, "context()")

[mhpob]

This is the issue I let you know introduced during our meeting...

FWIW I've been trying to go through and fix via updating to 3e

https://github.com/mhpob/glatos/tree/dev-testthat-3e

Currently about 75% of the way through the current tests (which I how I found #200)

[mhpob]

Closed by #204