[DEVEL] Unnecessary use of $ / ${} with arithmetic variable SH-2004 critical anti-pattern

Description

escription
Use of $ or ${..} on regular variables in arithmetic context is unnecessary, and can even lead to subtle bugs. This is because the content of $((..)) is first expanded into a string, and then evaluated as an expression:

$ a='1+1'
$ echo $(($a * 5))    # becomes 1+1*5
6
$ echo $((a * 5))     # evaluates as (1+1)*5
10
The $ is unavoidable for special variables like $1 vs 1, $# vs #. It is also required when adding modifiers to parameters expansions, like ${#var} or ${var%-}.

Problematic code:
echo $(($n + ${arr[i]}))
Preferred code:
echo $((n + arr[i]))

$/${} is unnecessary on arithmetic variables found here:

https://github.com/philipjonsen/chainlink/blob/develop/tools/benchmark/job_spec_delete_v2.sh#L143-L143

$/${} is unnecessary on arithmetic variables found here:

https://github.com/philipjonsen/chainlink/blob/develop/tools/benchmark/job_spec_delete_v2.sh#L134-L134

Open tools/benchmark/job_spec_delete_v2.sh and inspect the arithmetic expressions at lines 134 and 143. Remove the unnecessary variable expansions in those expressions, then review the surrounding shell syntax to confirm the script still uses the intended arithmetic evaluation.