fix(deps): update module maunium.net/go/mautrix to v0.26.3

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
maunium.net/go/mautrix	v0.26.2 → v0.26.3

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Release Notes

mautrix/go (maunium.net/go/mautrix)

v0.26.3

Compare Source

• Bumped minimum Go version to 1.25.
• (client) Added fields for sending MSC4354 sticky events.
• (bridgev2) Added automatic message request accepting when sending message.
• (mediaproxy) Added support for federation thumbnail endpoint.
• (crypto/ssss) Improved support for recovery keys with slightly broken
  metadata.
• (crypto) Changed key import to call session received callback even for
  sessions that already exist in the database.
• (appservice) Fixed building websocket URL accidentally using file path
  separators instead of always /.
• (crypto) Fixed key exports not including the sender_claimed_keys field.
• (client) Fixed incorrect context usage in async uploads.
• (crypto) Fixed panic when passing invalid input to megolm message index
  parser used for debugging.
• (bridgev2/provisioning) Fixed completed or failed logins not being cleaned
  up properly.

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[renovate]

ℹ️ Artifact update notice

File name: go.mod

In order to perform the update(s) described in the table above, Renovate ran the go get command, which resulted in the following additional change(s):

• 6 additional dependencies were updated
• The go directive was updated for compatibility reasons

Details:

Package	Change
go	1.24.10 -> 1.25.0
go.mau.fi/util	v0.9.5 -> v0.9.6
golang.org/x/crypto	v0.47.0 -> v0.48.0
golang.org/x/exp	v0.0.0-20260112195511-716be5621a96 -> v0.0.0-20260212183809-81e46e3db34a
golang.org/x/net	v0.49.0 -> v0.50.0
golang.org/x/sys	v0.40.0 -> v0.41.0
golang.org/x/text	v0.33.0 -> v0.34.0