[ci] #2153: Fix #2154

[s8sato]

Description of the Change

• Add a step to add llvm-tools-preview component

Issue

• Closes Fix coverage #2153
• Opens Remove duplicated llvm-tools-preview installation in CI #2165

Benefits

• Enables the coverage by fixing the error that [ci] #2153: Fix coverage #2154 did not resolve

Possible Drawbacks

• CI cost by the duplicated step which should have been done in the container, which could be cut off

[codecov]

Codecov Report

Merging #2166 (410b8b2) into iroha2-dev (2a94dba) will decrease coverage by 0.09%.
The diff coverage is 72.86%.

❗ Current head 410b8b2 differs from pull request most recent head c2fddd2. Consider uploading reports for the commit c2fddd2 to get more accurate results

@@              Coverage Diff               @@
##           iroha2-dev    #2166      +/-   ##
==============================================
- Coverage       77.27%   77.17%   -0.10%     
==============================================
  Files             176      182       +6     
  Lines           24216    25916    +1700     
==============================================
+ Hits            18713    20001    +1288     
- Misses           5503     5915     +412     

Impacted Files	Coverage Δ
client/benches/tps/lib.rs	0.00% <0.00%> (ø)
client/benches/tps/oneshot.rs	0.00% <0.00%> (ø)
client/examples/million_accounts_genesis.rs	0.00% <0.00%> (ø)
client/src/lib.rs	100.00% <ø> (ø)
client/tests/integration/connected_peers.rs	100.00% <ø> (+10.00%)	⬆️
...lient/tests/integration/multiple_blocks_created.rs	0.00% <0.00%> (ø)
client/tests/integration/unregister_peer.rs	0.00% <0.00%> (-100.00%)	⬇️
client/tests/integration/unstable_network.rs	0.00% <0.00%> (ø)
client_cli/src/main.rs	0.30% <0.00%> (-0.03%)	⬇️
config/src/lib.rs	16.66% <ø> (ø)
... and 165 more

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[s8sato]

Closed because the coverage contains target/debug/build for some reason and has dropped to about 70% from previous about 78%

[s8sato]

Resolved the coverage regression