[BUG] erpcgen fails when generating union with string for C

[KomarekJan]

Describe the bug
Erpcgen fails when generating shim code for C from IDL file that contains union with string.

To Reproduce

program testUnion

enum { A, B }

union unionWithString {
    case A:
        string b
    case B:
        int32 a
}

struct C {
    int32 discriminator
    unionWithString data @discriminator(discriminator)
}

interface test {
    unionTest(C a) -> void
}

On Windows fails with the exit code -1073741819

Expected behavior
Generate shim code.

Screenshots

Desktop (please complete the following information):

• OS: Windows 10
• eRPC Version: v1.10.0

Steps you didn't forgot to do

• I checked if there is no related issue opened/closed.
• I checked that there doesn't exist opened PR which is solving this issue.

Additional context

[github-actions]

Hi eRPC user. Thank you for your interest and welcome. We hope you will enjoy this framework well.