fix(expect): improve event log capture logic

Refines the capture_log procedure to use less greedy regex matching and
ensure the end marker is not missed. This resolves issues where the log
capture would terminate early or skip digest contents. Also tolerates
whitespace differences to avoid false mismatches due to formatting.

Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
Co-authored-by: Chris Kay <chris.kay@arm.com>
Change-Id: Ieabccd81a0d191e817884a69327935f493df1a6a
2 files changed