fix: missing separator in MinerEvaluationCache.get() log message

[njlazzar-su]

Summary

Fix malformed log message in MinerEvaluationCache.get() when a cache identity mismatch occurs.

Problem

The debug log message uses Python implicit string concatenation across multiple lines, but the last line is a plain string (not an f-string) and is missing a separator:

bt.logging.debug(
    f"...github_id={github_id})"
    "Removing cached evaluation"  # Missing f-prefix and separator
)

This produces output like:

Cache miss for UID 5: ...github_id=123)Removing cached evaluation

Instead of:

Cache miss for UID 5: ...github_id=123). Removing cached evaluation

Fix

• Add f-string prefix to the last line
• Add period and space separator between the parenthesis and "Removing"

[anderdc]

needs to target test branch

[njlazzar-su]

fixed