fix(logstorage): decrement g_logstorage_cache_size on filter config free

[aki1770-del]

Problem

dlt_logstorage_filter_config_free() calls free(data->cache) but never decrements the global g_logstorage_cache_size counter.

The counter is incremented during cache allocation in dlt_logstorage_create_cache():

g_logstorage_cache_size += cache_size + sizeof(DltLogStorageCacheFooter);

But on the free path the decrement is missing, so the counter grows unboundedly across disable/re-enable cycles. After enough cycles, g_logstorage_cache_size reaches g_max_logstorage_cache_size even with no active caches, causing all subsequent dlt_logstorage_create_cache() calls to fail with "Max cache size reached".

Reported in #778.

Fix

Before free(data->cache), compute the same cache_size value that was used during allocation and subtract it from g_logstorage_cache_size. Clamp to zero to guard against any bookkeeping inconsistency.

if (data->cache != NULL) {
    unsigned int cache_size = 0;
    if (DLT_OFFLINE_LOGSTORAGE_IS_STRATEGY_SET(data->sync,
            DLT_LOGSTORAGE_SYNC_ON_SPECIFIC_SIZE) > 0)
        cache_size = data->specific_size;
    else
        cache_size = data->file_size;
    cache_size += (unsigned int)sizeof(DltLogStorageCacheFooter);
    if (g_logstorage_cache_size >= cache_size)
        g_logstorage_cache_size -= cache_size;
    else
        g_logstorage_cache_size = 0;
    free(data->cache);
    data->cache = NULL;
}

Testing

Verified manually: repeated logstorage enable/disable cycles no longer exhaust the cache counter.