[sonic-sairedis][sonic-swss-common] Update submodules

[smaheshm]

<- Why I did it
Linker error when compiling with ENABLE_SYNCD_RPC. Fix is in SAI repo.

• How I did it
  Moved variable declaration to object file included in librpcserver.a

• How to verify it
  compile with 'ENABLE_SYNCD_RPC" flag enabled.

• Description for the changelog

[sonic-sairedis]

update submodule to include SAI1.6.1.

[MultiDB] use get API to obtain dbid instead of hardcode value (#618) …
dzhangalibaba

Add synchronous mode to sairedis library (#617) …
kcudnik

[meta] Fix tests to be backward compatible (#619)
kcudnik

[sonic-swss-common]

EVPN VXLAN DB support (#339) …
srj102
tapashdas

Add modifyRedis flag to consumer table object (#344) …
kcudnik

Fix memory leak in pyext when Selectable is returned to Python (#343) …
pavel-shirshov

• A picture of a cute animal (not mandatory but encouraged)

[smaheshm]

Original draft PR is #4708

[jleveque]

@smaheshm: FYI, I updated the PR title to align with our standard convention.

[smaheshm]

retest vsimage please