fix(deps): update dependency grpcio to v1.68.0

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
grpcio (source)	1.67.1 -> 1.68.0

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Release Notes

grpc/grpc (grpcio)

v1.68.0

Compare Source

This is release 1.68.0 (groovy) of gRPC Core.

For gRPC documentation, see grpc.io. For previous releases, see Releases.

This release contains refinements, improvements, and bug fixes, with highlights listed below.

Core

• [XdsClient][Backport] Add missing authority to XdsClient metrics scope (#​38009). (#​38023)
• [Release] Bump core version in preparation for 1.68 Branch Cut. (#​37941)
• [ConfigFetcher] Set HTTP2 error to NO_ERROR to do graceful GOAWAYs. (#​37939)
• [ruby] reduce INFO log for server CQ pluck registration to DEBUG. (#​37633)
• [EventEngine] Enable the PosixEventEngine client experiment. (#​35985)
• [chttp2_server] Fix race between connection starting and it being orphaned. (#​37683)
• [Chttp2Server] Fix race between connection manager updates and handshake. (#​37772)
• [xds] Fix XdsClient race between ResourceDoesNotExist timer and receiving resources. (#​37678)

C++

• [Build] Minimum version of MSVC is now 2022. (#​37687)
• [Build] Bumped the minimum version of cmake. (#​37702)

Python

• Add templating and support for Python 3.13. (#​37643)

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Test Results

    40 files  ±0      40 suites  ±0   52m 34s ⏱️ - 5m 11s
   700 tests ±0     700 ✅ ±0      0 💤 ±0  0 ❌ ±0 
17 000 runs  ±0  15 930 ✅ ±0  1 070 💤 ±0  0 ❌ ±0 

Results for commit a6f8adb. ± Comparison against base commit c80af00.