Validate EMR_EXTCREATEPEN style entry count before allocation

[jmestwa-coder]

Summary

Validate the EMR_EXTCREATEPEN style entry count before allocating the dash pattern array.

Changes

• Add HemfPicture.safelyAllocateCheck(numStyleEntries) before allocating the dash pattern array.
• Reuse the existing HEMF allocation validation mechanism already used in related parser paths.
• Reject oversized style entry counts before attempting memory allocation.

Why

• numStyleEntries is read from EMF input and directly controls array allocation size.
• A malformed record can request an excessively large allocation, leading to resource exhaustion or allocation failures.
• This change ensures allocation limits are enforced consistently across HEMF record parsers.

Impact

• No behavior change for valid EMF files.
• Oversized or malformed inputs now fail through the existing validation path instead of attempting allocation.
• Aligns EMR_EXTCREATEPEN with the recent HEMF allocation-hardening updates.

[pjfanning]

duplicate of #1113

I'll also point you to #1113 (comment)

I probably won't merge many more changes like this and won't even read them.