[sairedis] Change static variable to use smart pointers instead of raw pointers

[liorghub]

Why I did it

To fix a memory issue.

How I did it

Used smart pointers in order for memory to be released when not being referenced anymore.

How to verify it

Run auto negotiation interfaces tests.
On 202205 latest, the following leaks occur, after the fix issue not reproduced.

Direct leak of 96 byte(s) in 1 object(s) allocated from:
    #0 0x7f5076865647 in operator new(unsigned long) ../../../../src/libsanitizer/asan/asan_new_delete.cpp:99
    #1 0x55a6717aad43 in declare_static<syncd::SwitchNotifications::SlotBase, syncd::SwitchNotifications::Slot, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15> syncd/SwitchNotifications.cpp:113
    #2 0x55a6717aad43 in declare_static<syncd::SwitchNotifications::SlotBase, syncd::SwitchNotifications::Slot, 16> syncd/SwitchNotifications.cpp:120
    #3 0x55a6717aad43 in __static_initialization_and_destruction_0 syncd/SwitchNotifications.cpp:124
    #4 0x55a6717aad43 in _GLOBAL__sub_I_SwitchNotifications.cpp syncd/SwitchNotifications.cpp:160

Direct leak of 32 byte(s) in 1 object(s) allocated from:
    #0 0x7f5076865647 in operator new(unsigned long) ../../../../src/libsanitizer/asan/asan_new_delete.cpp:99
    #1 0x55a6717aa680 in declare_static<syncd::ServiceMethodTable::SlotBase, syncd::ServiceMethodTable::Slot, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9> syncd/ServiceMethodTable.cpp:74
    #2 0x55a6717aa680 in declare_static<syncd::ServiceMethodTable::SlotBase, syncd::ServiceMethodTable::Slot, 10> syncd/ServiceMethodTable.cpp:81
    #3 0x55a6717aa680 in __static_initialization_and_destruction_0 syncd/ServiceMethodTable.cpp:85
    #4 0x55a6717aa680 in _GLOBAL__sub_I_ServiceMethodTable.cpp syncd/ServiceMethodTable.cpp:121

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205
• 202211

[kcudnik]

this is actually good change, why closed?